auto-HSCT Recipients Research Articles

Invasive fungal infections are rare in pediatric and young adult autologous hematopoietic stem cell transplant patients.

Pediatric and young adult patients undergoing autologous hematopoietic stem cell transplant (auto-HSCT) face a crucial, yet understudied, risk of invasive fungal infections (IFI), especially compared to allogeneic transplants. This gap underscores the need for research in pediatric patients undergoing auto-HSCT. Our objective was to evaluate the incidence of IFI in pediatric and young adult patients during the first year after auto-HSCT. We conducted a single-center retrospective analysis of 150 pediatric and young adult auto-HSCT patients who underwent transplant from January 2013 to January 2023. We focused on IFI incidence within the first-year post transplant, using the European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) criteria for IFI identification. Among the 150 patients analyzed, with 240 unique transplant episodes, the primary indication was neuroblastoma (37.3%), and micafungin was extensively used for prophylaxis (82.7%). There was an absence of IFI from yeast and mold species, suggesting a low IFI risk in this cohort. The incidence of IFI in pediatric auto-HSCT recipients receiving micafungin primary antifungal prophylaxis is rare. The findings advocate for further research to refine prophylaxis guidelines and highlight the need for individualized risk assessment to optimize post-transplant care.

P06 The effect of ciprofloxacin prophylaxis during haematopoietic cell transplantation on infection episodes, exposure to treatment antimicrobials and antimicrobial resistance: a single-centre retrospective cohort study

Abstract Background Fluroquinolone prophylaxis during haematopoietic cell transplantation (HCT) remains contentious. Objectives To determine the effectiveness of ciprofloxacin prophylaxis across different HCT indications and its association with exposure to treatment antimicrobials and antimicrobial resistance. Methods All admission episodes for HCT (N=400) in a tertiary centre between January 2020 and December 2022 were studied. Allogeneic haematopoietic cell transplantation (allo-HCT) recipients received prophylaxis with ciprofloxacin during chemotherapy-induced neutropenia, while autologous haematopoietic cell transplantation (auto-HCT) recipients did not. Results Allo-HCT was performed for 43.3% (173/400) of patients, auto-HCT for 56.7% (227/400). Allo-HCT was associated with an average of 1.01 fewer infection episodes per 100 admission days (95% CI 0.62–1.40, P<0.001) compared with auto-HCT. In allo-HCT, the total exposure to all antimicrobials was higher (+24.8 days of therapy [DOT]/100 admission days, P<0.001), as was exposure to ciprofloxacin (+40.5 DOT/100 admission days, P<0.001). In contrast, exposure to meropenem (−4.5 DOT/100 admission days, P=0.02), piperacillin/tazobactam (−5.2 DOT/100 admission days, P<0.001), aminoglycosides (−4.5 DOT/100 admission days, P<0.001), glycopeptides (−6.4 DOT/100 admission days, P<0.001), was reduced. Enterobacteriaceae isolated during allo-HCT were more resistant to ciprofloxacin (65.5%, 19/29 versus 6.1%, 2/33, P<0.001), ceftriaxone (65.5%, 19/29 versus 9.1%, 3/33, P<0.001), and other antimicrobial classes. Vancomycin-resistant enterococci were more common in allo-HCT recipients (11%, 19/173 versus 0.9%, 2/227, P<0.001). Inpatient mortality during allo- and auto-HCT was 9.8% (17/173) and 0.4% (1/227) respectively (P<0.001). An invasive bacterial infection was documented in 31.3% (125/400) of cases. Allo-HCT patients were more likely to have an invasive Gram-positive bacterial infection (23.1% versus 12.8%, P=0.01), while a difference was not observed for invasive Gram-negative bacterial infections (19.7% versus 18.5%, P=0.77). Among auto-HSCT recipients, patients with germ cell tumours had the highest probability (P for trend 0.03) of recording an invasive bacterial infection (12/23, 52.2%, 95% CI 31.3–74) compared with other indication for auto-HCT. Conclusions Ciprofloxacin prophylaxis in allo-HCT was associated with fewer infection episodes and reduced exposure to treatment antimicrobials. Mortality in auto-HCT remained low. A significant burden of antimicrobial resistance was detected in allo-HCT recipients. HCT recipients due to germ cell tumours, not receiving ciprofloxacin prophylaxis, recorded the highest incidence of invasive bacterial infections and represent a possible target group for this intervention.

Real-world challenges in eligibility for MMR vaccination two years after autologous and allogeneic HSCT

Measles outbreaks have raised concerns of fatal infections in immunocompromised patients. Canadian guidelines advise administration of live vaccines, such as measles, mumps, and rubella (MMR), two yearsafter hematopoietic stem cell transplant (HSCT) yet studies have not assessed eligibility based on medication contraindications. We retrospectively reviewed the charts of 72 autologous (auto-HSCT) and 68 allogeneic (allo-HSCT) recipients at the Windsor Regional Cancer Center to determine MMR reactivity and eligibility based on administration of contraindicated medications two years post-HSCT. Reactivity to measles, mumps, and rubella in auto-HSCT recipients was 49.1 %, 28.8 %, and 52.3 %, respectively, and in allo-HSCT recipients was 75.6 %, 57.8 %, and 64.4 %, respectively. Immunity to all three components was significantly different between transplant types (p = 0.0002). Nearly 80 % of auto-HSCT patients were on a contraindicated medication at two years compared to 45 % of allo-HSCT recipients. Auto-HSCT recipients require MMR revaccination, but it is contraindicated in a large proportion of patients.

P1221: DIFFUSE LARGE B-CELL LYMPHOMA RICHTER SYNDROME IN CHRONIC LYMPHOCYTIC LEUKEMIA – A RETROSPECTIVE ANALYSIS OF TREATMENT OUTCOMES IN POLISH ADULT LEUKEMIA STUDY GROUP

Background: Richter syndrome (RS) is a recognized uncommon manifestation and evolution of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) with a dismal prognosis. It occurs in 2-10% of CLL patients. It is associated with a clonal evolution and progression, generally with a transformation of the original CLL clone to diffuse large B-cell lymphoma (DLBCL) or, less frequently, to Hodgkin Lymphoma (HL). Despite the advances in understanding pathogenesis of the disease, the DLBCL variant of RS (DLBCL-RS) is associated with a dismal prognosis with a median survival < 1 year. The treatment options and risk factors of worse outcome for RS still need to be further expanded. Aims: To study the characteristic and treatment outcomes of patients with DLBCL-RS. Methods: The retrospective analysis of 99 patients diagnosed with DLBCL-RS treated in hematology centers of the Polish Adult Leukemia Study Group (PALG) between 2011 and 2021. Results: Clinical data of 124 patients with Richter syndrome was collected. Ninety-nine patients were diagnosed with DLBCL-RS (79.8%) and further analyzed. Median time since CLL diagnosis to Richter transformation was 43.0 months (range 0-252.0). At the time of transformation 31.3% patients had CLL Rai stage IV, 74.7% were ECOG< 2, while the median Cumulative Illness Rating Scale (CIRS) was 4 (range 0-16). Thirty-seven patients transformed during CLL treatment, 56.7% of them were receiving novel agents (Brutons tyrosine kinase inhibitor or BCL2 inhibitor). Median time of observation after transformation was 10.7 months (range 0-98.6). Median overall survival (OS) after DLBCL-RS diagnosis was 17.3 months (95% Cl 11.9-46.8) and median progression-free survival (PFS) 13.5 months (95% Cl 9.6-22.7). Seventy-six patients (76.8%) had RS treated with intensive chemotherapy protocols, mainly R-CHOP-like regimens for the first line treatment. Only 42.3% had response to the treatment (25/76 complete responses and 11/76 partial responses). Worth mentioning is that in the group of patients with response two patients had ibrutinib monotherapy and one had rituximab-ibrutinib. In forty patients RS was primarily resistant to administered treatment and 65% of them died due to progression or treatment related complications. In the primary resistant DLBCL-RS p53 pathway aberration was noted in 47.5% of patients (17p deletion in 13 patients or TP53 mutation in 6 patients). Better results were achieved for patients who proceeded to autologous hematopoietic stem cell transplantation (auto-HSCT; n=8) and allogeneic HSCT (allo-HSCT; n=10). The median OS in auto-HSCT recipients was 46.1 months, while in allo-HSCT the median OS reached 18.3 months (3 patients died due to allo-HCST-related complications). Significantly lower OS (3.4 months, 95% Cl 14.13-not reached) was observed for RS in heavily pretreated CLL patients (>3 lines of therapy preceding transformation) compared to those treated with up to 3 lines of therapy (23.7 months) (p=0.0002). Median OS for treatment naïve patients at DLBCL-RS diagnosis was not reached. Other factors identified as predictors of poor OS in univariate analysis were ECOG ≥2 (p=0.0014), hemoglobin level <10 g/dl (p=0.017) and platelet count <100x109/L (p=0.0065). Summary/Conclusion: Our study represents the largest dataset of DLBCL-RS patients in Polish hematology centers and confirms the poor outcomes and prognosis associated with RS. The worst treatment results were observed in RS receiving >3 lines of CLL therapy preceding transformation. Only proceeding to hematopoietic stem cell transplantation may improve the prognosis.

Bacteremia with Carbapenemase-Producing Enterobacterales in Immunocompromised Patients Colonized with These Bacteria.

We aimed to analyze rates and risk factors for carbapenemase-producing Enterobacterales (CPE) bloodstream infection (BSI) in CPE-colonized patients with malignancies or following hematopoietic cell transplantation. We retrospectively collected data on demography, underlying disease, colonizing CPE, treatment, intensive care unit (ICU) hospitalization, CPE-BSI, and mortality in CPE-colonized immunocompromised patients (2014-2020). Two hundred twenty-one patients were colonized with 272 CPE: 254 (93.4%) carried one carbapenemase [KPC (50.4%), NDM (34.6%), OXA-48-like (5.2%), and VIM (3.3%)]; 18 (6.6%) carried two carbapenemases. Twenty-eight (12.7%) patients developed CPE-BSI. Univariate analysis revealed CPE-BSI-associated factors: younger age, carbapenem or aminoglycoside exposure, ICU admission, neutropenia, carrying serine carbapenemase-producing, and specifically KPC-producing bacteria, colonization with several CPE, and detection of several carbapenemases. None of 23 auto-HSCT recipients developed CPE-BSI. In multivariate analysis, ICU hospitalization was significantly associated with CPE-BSI (odds ratio [OR] 2.82, 95% CI 1.10-7.20; p = 0.042); solid tumor diagnosis was protective (OR 0.21, 95% CI 0.05-1.01; p = 0.038). One-year crude mortality was 108/221 (48.8%), including 19/28 (67.9%) and 89/193 (46.1%) in patients with and without CPE-BSI, p = 0.104. To conclude, CPE-BSI is rare in CPE-colonized patients with solid tumors and following auto-HSCT. ICU hospitalization increased CPE-BSI risk. These data can help to guide empirical anti-CPE antibiotic therapy in patients colonized with these bacteria.

Hematopoietic Stem Cell Transplantation in Nepal: International Partnership, Implementation Steps, and Clinical Outcomes

Blood and marrow transplantation (BMT) is rarely available in many low- to middle-income countries (LMICs). In 2012, Civil Service Hospital, a government hospital in Kathmandu, partnered with the University of Illinois at Chicago to consult on the establishment of BMT in their hospital, train staff, and promote educational activities. The implementation of BMT occurred in 3 phases over 4 years and included regular onsite visits, training of personnel in Chicago, continuous remote communication, and co-organization of educational events in Kathmandu. The Nepalese government funded the construction of a state-of-the art BMT unit and stem cell laboratory inside Civil Hospital. Autologous (auto) hematopoietic stem cell transplantation (HSCT) was started in 2016, and allogeneic (allo) HSCT from matched related donors (MRDs) or haploidentical (haplo) donors was initiated in 2017. The cost of transplantation was $5200 for auto-HSCT, $10,000 for MRD HSCT, and $13,300 for haplo HSCT. The major socioeconomic determinants reported by Nepalese BMT providers were the cost of transplantation, loss of revenue of the patient and/or caregiver, and cost of transportation. All patients (n=66) received peripheral blood stem cell grafts, and all allo-HSCT recipients were given post-transplantation cyclophosphamide as graft-versus-host disease (GVHD) prophylaxis. Among recipients of auto-HSCT (n=30), with a median follow-up of 1029 days (range, 130 to 1653 days), 87% were alive, and transplantation-related mortality (TRM) was 10%. Among allo-HSCT recipients (n=36), all patients engrafted, and at a median follow-up of 204 days (range, 12 to 1131 days), 75% of them were alive (MRD, 71%; haplo, 83%), with a TRM of 19%. Only 3 of 36 patients developed acute GVHD grade II-IV. The median overall survival in auto-HSCT recipients was 1610 days and was not reached in allo-HSCT recipients. The long-lasting partnership with University of Illinois at Chicago helped build capacity and allowed the Civil Service Hospital team to establish a BMT program in Nepal that has high quality standards at an affordable cost for the majority of patients.

Vaccine Responses in Adult Hematopoietic Stem Cell Transplant Recipients: A Comprehensive Review.

Simple SummaryPatients who recently received a stem cell transplantation are at greater risk for infection due to impairment of their immune system. In order to prevent severe infection, these patients are vaccinated after their stem cell transplantation with childhood immunization vaccines. Timing of this vaccination is important in order to be effective and obtain proper immune response. Postponement of vaccination would lead to better immune response but would also cause longer-lasting risk of infection. This review describes available data on the timing of vaccination and its vaccine responses. Optimal timing of vaccination might require an individualized approach per patient.Consensus on timing of post-hematopoietic stem cell transplantation (HSCT) vaccination is currently lacking and is therefore assessed in this review. PubMed was searched systematically for articles concerning vaccination post-HSCT and included a basis in predefined criteria. To enable comparison, data were extracted and tables were constructed per vaccine, displaying vaccine response as either seroprotection or seroconversion for allogeneic HSCT (alloHSCT) and autologous HSCT (autoHSCT) separately. A total of 33 studies were included with 1914 patients in total: 1654 alloHSCT recipients and 260 autoHSCT recipients. In alloHSCT recipients, influenza vaccine at 7–48 months post-transplant resulted in responses of 10–97%. After 12 months post-transplant, responses were >45%. Pneumococcal vaccination 3–25 months post-transplant resulted in responses of 43–99%, with the response increasing with time. Diphtheria, tetanus, pertussis, poliomyelitis and Haemophilus influenzae type b at 6–17 months post-transplant: 26–100%. Meningococcal vaccination at 12 months post-transplant: 65%. Hepatitis B vaccine at 6–23 months post-transplant: 40–94%. Measles, mumps and rubella at 41–69 months post-transplant: 19–72%. In general, autoHSCT recipients obtained slightly higher responses compared with alloHSCT recipients. Conclusively, responses to childhood immunization vaccines post-HSCT are poor in comparison with healthy individuals. Therefore, evaluation of response might be indicated. Timing of revaccination is essential for optimal response. An individualized approach might be necessary for optimizing vaccine responses.

Allogeneic and Autologous Hematopoietic Transplants Can be Safely Performed after COVID-19 Infections

We are in the midst of a pandemic with the COVID-19 virus, a pathogen with potential severe manifestations. A major clinical question is whether it is safe to undergo hematopoietic stem cell transplantation (HSCT) shortly after COVID-19 infection. A total of 21 patients received HSCT following a diagnosis of COVID-19 infection at our institution between 7/30/2020 and 4/14/2021. The majority (n=13, 62%) received an allogeneic (ALLO) HSCT from an HLA-matched related (n=5), -matched unrelated (n=6), or haploidentical (n=2) donor. The remaining 8 patients received autologous (AUTO) HSCT. Among ALLO-HSCT recipients, 4 (31%), 5 (38%), 3 (23%), and 1 (8%) patients had grade 1, 2, 3, and 4, manifestations respectively, scored according to the WHO COVID-19 infection severity grading system. Among AUTO-HSCT recipients, 5 (62%), 1 (12%), and 2 (25%) patients had grade 0, 1, and 2 manifestations, respectively. All patients had resolution of COVID-19 symptoms before HSCT. In recipients of ALLO-SCT, the median time from diagnosis of the COVID infection to HSCT was 134 (range: 55-311) days. Median age of recipients was 53 (range: 17-71) years and the majority (69%) of patients were male. Only one patient was <18 years old, and 38% were >60 years. Patients received ALLO-HSCT for treatment of acute myeloid leukemia or myelodysplastic syndrome (n=7, 54%), acute lymphoblastic leukemia (n=2, 15%), chronic lymphoblastic leukemia (n=2, 15%), and Hodgkin's (n=1, 8%) or non-Hodgkin's lymphoma (n=1, 15%). Most (62%) patients were not in remission at the time of HSCT. The median hematopoietic cell transplant-co-morbidity index (HCT-CI) score was 3 (range 0-6); one patient had a history of diabetes and another of hypertension before HSCT. Conditioning regimen was myeloablative in 61%, and stem cell source was peripheral blood (PB) in 92% of transplants. Median time to neutrophils engraftment was 15 (range: 10-20) days. With a median follow-up of 3.5 (range: 0.4-8) months since ALLO-HSCT, two patients died and another two experienced progression of the underlying malignancy. Three patients were diagnosed with grade 2 and none with grade 3 or 4 acute graft-versus-host disease (GvHD). The deaths occurred among patients with COVID-19 infection grade 2 and 3. The primary cause of death was attributed to alveolar hemorrhage/pneumonitis (no organism identified) and acute GvHD, respectively. Overall survival was 89% (95% confidence interval [CI]:43-98) and 76% (95% CI 33-93) at 3 and 6 months, respectively. In recipients of AUTO-HSCT, the median time from diagnosis of the COVID-19 infection to HSCT was 55 (range: 20-157) days. Median age of recipients was 55 (range: 34-75) years, and the majority (62%) of patients were male. One (12%) patient was >60 years. Patients received AUTO-HSCT for treatment of Hodgkin's (n=1, 15%) or non-Hodgkin's (n=4, 50%) lymphoma, or multiple myeloma (n=3, 37%). Six (75%) patients were in remission at the time of HSCT. The median HCT-CI score was 2 (range 0-6). None of the patients had a history of diabetes or hypertension before transplant. Conditioning regimen was myeloablative and stem cell source was PB for all patients. Median time to neutrophils engraftment was 10 (range: 9-13) days. With a median follow-up of 4 (range: 0.8-9) months since AUTO-HSCT, one patient with grade 1 COVID infection died as a result of a candida/cytomegalovirus infection, and none of the patients experienced progression of the underlying malignancy. Overall survival was 100% and 75% (95% CI 13-96) at 3 and 6 months respectively. After HSCT, one ALLO and two AUTO asymptomatic patients had a positive nasal swab COVID-19 PCR assay possibly due to delayed shedding of the virus. None of the 21 patients developed active COVID infections post-transplant. In conclusion, allogeneic and autologous hematopoietic transplantation can be performed in patients after COVID-19 infection. Two of 13 allogeneic and one of 8 autologous recipients experienced non-relapse mortality, none directly related to COVID-19 infection. Patients recovering from COVID-19 infection should be considered eligible for hematopoietic transplantation as clinically indicated. DisclosuresShpall: Magenta: Honoraria; Affimed: Patents & Royalties; Novartis: Honoraria; Navan: Consultancy; Magenta: Consultancy; Axio: Consultancy; Adaptimmune: Consultancy; Bayer HealthCare Pharmaceuticals: Honoraria; Novartis: Consultancy; Takeda: Patents & Royalties. Chemaly: Other: Other: Compensation: I am a consultant and advisor on companies who are developing new agents such as Merck, Ansun, and Janssen.

Clinical characteristics and incidence of toxoplasmosis after autologous hematopoietic stem cell transplantation: A retrospective study and literature review.

Toxoplasmosis is a rare but life-threatening infection occurring in immunocompromised hosts, including allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. However, thus far, the clinical features and incidence of toxoplasmosis in autologous HSCT (auto-HSCT) recipients remain unknown. This retrospective survey aimed to analyze 152 patients who received auto-HSCT between 1998 and 2017. Serological tests for Toxoplasma gondii-specific IgG were performed on 109 (71.7%) recipients, and 12 pre-HSCT recipients (11%) were Toxoplasma seropositive. Among the 12 recipients, three who did not receive trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis developed cerebral, pulmonary or disseminated toxoplasmosis due to reactivation after auto-HSCT and died despite treatment. The incidences of toxoplasmosis were 2% and 25% among 152 auto-HSCT recipients (five recipients received auto-HSCT two times) and 12 pre-HSCT Toxoplasma seropositive recipients, respectively. Further, we conducted a literature review and identified 21 cases of toxoplasmosis following auto-HSCT. In these previous cases, the mortality rate was high, especially for pulmonary and disseminated toxoplasmosis. Our findings suggest that, similar to toxoplasmosis after allo-HSCT, toxoplasmosis after auto-HSCT is a fatal complication. Serial screening of T. gondii-specific IgG before HSCT could contribute to the detection of Toxoplasma reactivation and allow for prompt diagnosis and treatment. The present study is the first to reveal the incidence of toxoplasmosis after auto-HSCT among seropositive patients in Japan.

Risk of reactivated toxoplasmosis in haematopoietic stem cell transplant recipients: a prospective cohort study in a setting withholding prophylaxis

ObjectivesReactivation of latent toxoplasmosis may be life-threatening in haematopoietic stem cell transplant (HSCT) recipients. We conducted an 8-year-long prospective study on the diagnosis and monitoring of reactivated toxoplasmosis in paediatric HSCT recipients. The primary objective was to determine the incidence of reactivated toxoplasmosis in a setting that withholds prophylaxis until engraftment. The second objective was to identify the subgroups of HSCT recipients particularly prone to reactivation who may benefit the most from regular PCR follow-up. MethodsSerological and qPCR screening targeting the Toxoplasma 529 bp gene was performed before HSCT, and continued by weekly monitoring after HSCT for a median time of 104 days. ResultsReactivated toxoplasmosis was diagnosed in 21/104 (20.2%), predominantly in allo- (19/75) and rarely in auto-HSCT (2/29) recipients. Over 50% (14/21) of cases were diagnosed during the first month after HSCT, while awaiting engraftment without prophylaxis. Toxoplasma disease evolved in only three (14.3%, 3/21) patients, all treated by allo-HSCT. Reactivation was more frequent in patients treated for acute lymphoblastic leukaemia (3/27, p 0.03) and especially, in recipients of haploidentical stem cells (10/20, p 0.005). Seronegative status of the donor (where was known) contributed to 75% (12/16) cases of reactivated toxoplasmosis after allo-HSCT. DiscussionThe presented results show that peripheral blood-based qPCR, both before and after HSCT, is a valuable asset for the diagnosis of reactivated toxoplasmosis, whereas the results of serology in recipients should be interpreted with caution. Weekly qPCR monitoring, at least until successful engraftment and administration of prophylaxis, allows for prompt introduction of specific treatment.

A multicenter retrospective study on the real-world outcomes of autologous vs. allogeneic hematopoietic stem cell transplantation for peripheral T-cell lymphoma in China.

Background:There were few studies on real-world data about autologous hematopoietic stem cell transplantation (auto-HSCT) or allogeneic HSCT (allo-HSCT) in peripheral T-cell lymphoma (PTCL). This study aimed to investigate the clinical outcomes of patients who received auto-HSCT or allo-HSCT in China.Methods:From July 2007 to June 2017, a total of 128 patients who received auto-HSCT (n = 72) or allo-HSCT (n = 56) at eight medical centers across China were included in this study. We retrospectively collected their demographic and clinical data and compared the clinical outcomes between groups.Results:Patients receiving allo-HSCT were more likely to be diagnosed with stage III or IV disease (95% vs. 82%, P = 0.027), bone marrow involvement (42% vs. 15%, P = 0.001), chemotherapy-resistant disease (41% vs. 8%, P = 0.001), and progression disease (32% vs. 4%, P < 0.001) at transplantation than those receiving auto-HSCT. With a median follow-up of 30 (2–143) months, 3-year overall survival (OS) and progression-free survival (PFS) in the auto-HSCT group were 70%(48/63) and 59%(42/63), respectively. Three-year OS and PFS for allo-HSCT recipients were 46%(27/54) and 44%(29/54), respectively. There was no difference in relapse rate (34%[17/63] in auto-HSCT vs. 29%[15/54] in allo-HSCT, P = 0.840). Three-year non-relapse mortality rate in auto-HSCT recipients was 6%(4/63) compared with 27%(14/54) for allo-HSCT recipients (P = 0.004). Subanalyses showed that patients with lower prognostic index scores for PTCL (PIT) who received auto-HSCT in an upfront setting had a better outcome than patients with higher PIT scores (3-year OS: 85% vs. 40%, P = 0.003). Patients with complete remission (CR) undergoing auto-HSCT had better survival (3-year OS: 88% vs. 48% in allo-HSCT, P = 0.008). For patients beyond CR, the outcome of patients who received allo-HSCT was similar to that in the atuo-HSCT group (3-year OS: 51% vs. 46%, P = 0.300).Conclusions:Our study provided real-world data about auto-HSCT and allo-HSCT in China. Auto-HSCT seemed to be associated with better survival for patients in good condition (lower PIT score and/or better disease control). For patients possessing unfavorable characteristics, the survival of patients receiving allo-HSCT group was similar to that in the auto-HSCT group.

Is stem cell transplantation still needed for adult Philadelphia chromosome-positive acute lymphoblastic leukemia receiving tyrosine kinase inhibitors therapy?: A systematic review and meta-analysis.

BackgroundHematopoietic stem cell transplantation (HSCT) is the current mainstay treatment for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). However, tyrosine kinase inhibitors (TKI) also play a significant role in the treatment of these patients. We conducted this systematic review and meta-analysis to compare the efficacy of allogeneic (allo-) HSCT, autologous (auto-) HSCT, and chemotherapy (CMT) alone–all in combination with TKIs in adult Ph+ ALL patients.Materials and methodsThis systematic review identified studies from the EMBASE and MEDLINE databases from inception to April 2021 using search terms related to “ALL” and “HSCT.” Eligible studies could be randomized controlled trials or cohort studies that included adult Ph+ ALL patients who received a TKI and either allo-HSCT, auto-HSCT, or CMT alone, and that reported the number of patients in each group for each of our primary outcomes of interest: overall survival (OS) or disease-free survival (DFS). Point estimates and associated 95% confidence intervals (CI) from each study were combined using the Hantel-Maenszel method.ResultsAfter two rounds of review, 26 cohort studies were determined to be eligible for the meta-analysis. Adult Ph+ ALL patients who received HSCT had better survival outcomes than those who did not receive any HSCT (pooled odds ratio [OR] for OS of 1.61, 95%CI: 1.08–2.40; I2 = 59%, and for DFS of 3.23, 95%CI: 2.00–5.23; I2 = 62% for allo-HSCT; and, pooled OR for OS of 7.04, 95%CI: 1.97–25.15; I2 = 0%, and for DFS of 5.78, 95%CI: 1.04–32.19; I2 = 42% for auto-HSCT). Allo-HSCT recipients had comparable OS and DFS, but lower relapse rate compared to auto-HSCT recipients. Funnel plot generally demonstrated no presence of publication bias.ConclusionsThis systematic review and meta-analysis demonstrated superior results of HSCT in Ph+ ALL patients compared to CMT alone. Moreover, auto-HSCT could be implemented with comparable survival outcomes to allo-HSCT in patients with no available donor or when haploidentical HSCT is not feasible.

Increased blood transfusion after outpatient autologous transplantation with reduced intensity conditioning for hematological malignancies predicts worse outcomes.

Transfusion has a recognized immunomodulatory effect, and its role on the outcomes after an ambulatory autologous hematopoietic stem cell transplantation (auto-HSCT) following reduced intensity conditioning (RIC) has not been documented. A study to assess factors associated with the number of packed red blood cells (PRBCs) and platelet units transfused and their impact on survival rates of auto-HSCT recipients after RIC was conducted between 2013 and 2019. Transfusions were recorded from days 0 to 100. Of the 130 patients studied, seventy (53.9%) required transfusion support. The median number of PRBC transfused was 2 (range 1-20), and for platelets, it was also 2 units (range 1-19). Infused CD34+cells/kg, pre-transplant CMV status, and relapse/progression were significantly associated with the number of PRBC units transfused and sex, infused CD34+cells/kg, and pre-transplant CMV status with the number of platelet units transfused. In multivariate analysis, a high/very high Disease Risk Index (P=.001) (P=.001) and transfusion of≥5 total blood products (P=.001) (P=.010) were associated with decreased disease-free and overall survival. Two-year cumulative incidence of relapse was 50% for transfused patients vs. 34% for those not transfused (P=.009). These data suggest that the transfusion burden and its interplay with other patient and transplant-related factors could be associated with inferior auto-HSCT outcomes.

Comparison of post-remission strategies in acute myeloid leukemia: Autologous hematopoietic stem cell transplantation versus consolidation chemotherapy.

Autologous Hematopoietic Stem Cell Transplantation (auto-HSCT) has become a therapeutic option for first-line consolidation in Acute Myeloid Leukemia (AML) patients with favorable and intermediate risk features. A total of 101 AML patients in first complete remission, who were not eligible for allogeneic HSCT, were randomized to receive intensive cytarabine-based chemotherapy or to undergo auto-HSCT. The probability of LFS was significantly better in auto-HSCT recipients compared to chemotherapy arm (43% vs 4.8%, p=0.008). At the end of 915 (30-4470) days of followup, the probability of overall survival was better in auto-HSCT group compared to chemotherapy, without statistical significance (79.2% vs 38.8%, p=0.054). Multivariate analysis revealed a significant predictive impact of cytogenetic risk status on OS (p=0.002, HR: 2.824, 95% CI: 1.445-5.521). Auto-HSCT is considered as an effective consolidation approach in favorable and intermadiate risk AML patients.

Impact of Sars-Cov-2 Infection in Hematopoietic Transplant Patients: Experience from the Madrid Group

Peter Paschka and Hartmut Döhner contributed equally.Background. SARS-CoV-2 infection (COVID-19) has had a great impact worldwide and its mortality has been reported to be higher in patients with haematological malignancies. However, description of its effects and outcomes among recipient of hematopoietic stem cell transplantation (HSCT) is scarce.Objectives. To describe the characteristics, treatment and outcome of COVID-19 in recipients of HSCT reported to the Madrid registry of COVID-19 (“HEMATO-MADRID COVID-19 registry”).Results. Data of 842 patients from 23 hospitals with haematological malignancies and COVID-19 infection were reported in the Madrid registry between March and June 2020. Among those, 87 (10.3%) patients were HSCT recipients: 58 auto-HSCT and 29 allo-HSCT (7 of them from matched related donor (MRD), 12 matched unrelated donor (MUD) and 10 haplo-HSCT). Characteristics of the population are described in Table 1. Median age at COVID-19 infection was 61 years (IQR, 53-67) and 35 patients (40%) were female. Recipients of auto-HSCT with COVID-19 were older and showed a trend towards a higher incidence of arterial hypertension (28% vs 10%, p=0.067) without statistical differences in other comorbidities; active disease requiring treatment at COVID-19 diagnosis was more frequent in auto-HSCT recipients (65% vs. 21%, p<0.001). Median time from transplant to COVID19 infection was shorter in allo-HSCT patients (32 vs. 19 months, p=0.043). Nearly 40% of allo-recipients had active GVHD at COVID-19 debut, including pulmonary GVHD. A total of 63 (72%) patients required hospital admission and 13 patients (15%) received intensive care support. Allo-recipients showed a trend towards a higher need of hospital admission (79% vs. 68%, p=0.081). Most patients received anti-viral treatment with either hydroxichloroquine (47 patients, 54%), lopinavir/ritonavir (34 patients, 39%), remdesivir (5, 4%) and/or other treatments including azythromicin or interferon. 23 patients (26%) received anticytokine treatment with tocilizumab (15, 17%) and/or anakinra (8, 9%) and 27 patients (31%) received steroids. The overall response rate to treatment and supportive care was 80% in both groups. After a median follow-up of 50 days after the infection debut, overall-survival at day 50 was 84% for auto and 82% for allo-HSCT recipients (p=0.915). However, global mortality rate among the complete observation period was significantly higher in allo-recipients (24% vs. 17%, p <0.001).Conclusion. In our multicentric experience in a high COVID-19 impacted area, the median time of COVID-19 infection presentation was relatively late in transplanted patients, however shorter in allo-transplanted patients. COVID-19 related mortality was high in HSCT recipients, significantly higher in allo-transplanted patients. Factors associated to this higher mortality should be further investigated to promptly identify high-risk patients since the pandemic is still highly active worldwide.DisclosuresKwon:Gilead: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Jazz: Consultancy, Honoraria. Duarte:Incyte Corporation: Other: Has received speaker and advisor fees. Hernandez-Rivas:Rovi: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees. Jimenez Yuste:NovoNordisk: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Grifols: Honoraria, Research Funding; Bayer: Honoraria; Sobi: Consultancy, Honoraria, Research Funding; CSL: Honoraria; Octapharma: Honoraria.

Clinical and biological characteristics of neuroblastoma in adolescents and young adults. Case study and literature review

Introduction. Neuroblastoma (NB) is the most common extracranial solid tumor in infants, but it is more rarely found in older children. Only 1–2 % of cases are registered in adolescents and young adults. The long-term prognosis in these patients is highly unfavorable due to indolent clinical course formed by peculiar biological characteristics of tumors. We publish a case study of 11 patients with NB older than 10 years at the time of diagnosis.Case series description. In 2008 to 2020 a total of 11 adolescent and young adults patients with median age of 14 (10–28) years were treated in Raisa Gorbacheva Memorial Research Institute of Children Oncology, Hematology and Transplantation, First Pavlov State Medical University of St. Petersburg. Seven of 11 patients had mediastinal neuroblastoma, in other cases the primary lesion was abdominal (n = 2), pelvic (n = 1), and in one case no primary lesion was defined. Ten of 11 patients had primary disseminated disease with lymph nodes (n = 5), bone (n = 5), bone marrow (n = 3), or hepatic (n = 1) metastases. Tumor morphology and cytogenetics were assessed in all patients, in 4 cases additional targeted sequencing of potentially pathogenic genes was performed. All patients received chemotherapy and local control measures according to high-risk NB guidelines, in 7 of 11 cases additional chemotherapy regimens were used. Seven of 11 patients also received dose-intensive consolidation with autologous hemopoietic stem cell transplantation (auto-HSCT). In case of primary resistance MIBG-therapy, targeted or immunotherapy were used. In 6 cases tumor morphology corresponded to undifferentiated neuroblastoma, in 5 cases to ganglioneuroblastoma. Although all cases were high-risk, they mostly lacked high-risk biological features seen in younger patients. None had MYCN amplification, the cytogenetic assay yielded the following aberrations: +2 (n = 2), del1p (n = 1), g17q (n = 1). All patients, in whom the targeted sequencing was performed had pathogenic mutations: ATRX (in two patients 19 and 28 years at diagnosis), TP53 and PIK3CA, FBXW7. Nine of 11 patients had primary resistant disease, in 7 cases response was obtained on second or subsequent therapy lines. Two patients responded two chemoand targeted therapy combination, in 3 cases monoor combined immunotherapy yielded prolonged (16–32 months) response. Six of 7 auto-HSCT recipients developed a relapse. 6 out of 11 patients are currently alive. In 2 cases, a complete response is maintained according to scintigraphy with 123I-MIBG, lasting 86 and 14 months after completion of therapy.Conclusions. NB is biologically different in adolescents and young adults. It is characterized by indolent clinical course with very high risk of late relapse. As most patients in this group are chemoresistant, the standard dose-intensive tactics may be less effective and perhaps more attention should be given to targeted and immunotherapy-based approaches.

Immunogenicity of Inactivated Varicella Zoster Vaccine in Autologous Hematopoietic Stem Cell Transplant Recipients and Patients With Solid or Hematologic Cancer.

BackgroundIn phase 3 trials, inactivated varicella zoster virus (VZV) vaccine (ZVIN) was well tolerated and efficacious against herpes zoster (HZ) in autologous hematopoietic stem cell transplant (auto-HSCT) recipients and patients with solid tumor malignancies receiving chemotherapy (STMc) but did not reduce HZ incidence in patients with hematologic malignancies (HMs). Here, we describe ZVIN immunogenicity from these studies.MethodsPatients were randomized to ZVIN or placebo (4 doses). Immunogenicity was assessed by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and VZV interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) assay in patients receiving all 4 doses without developing HZ at the time of blood sampling.ResultsEstimated geometric mean fold rise ratios (ZVIN/placebo) by gpELISA and IFN-y ELISPOT ~28 days post–dose 4 were 2.02 (95% confidence interval [CI], 1.53–2.67) and 5.41 (95% CI, 3.60–8.12) in auto-HSCT recipients; 1.88 (95% CI, 1.79–1.98) and 2.10 (95% CI, 1.69–2.62) in patients with STMc; and not assessed and 2.35 (95% CI, 1.81–3.05) in patients with HM.ConclusionsZVIN immunogenicity was directionally consistent with clinical efficacy in auto-HSCT recipients and patients with STMc even though HZ protection and VZV immunity were not statistically correlated. Despite a lack of clinical efficacy in patients with HM, ZVIN immunogenicity was observed in this population. Immunological results did not predict vaccine efficacy in these 3 populations.Clinical trial registrationNCT01229267, NCT01254630.

Comparative Analysis of Immune Reconstitution in HIV-Positive Recipients of Allogeneic and Autologous Stem Cell Transplant on the BMT-CTN-0903/AMC-080 and BMT-CTN-0803/AMC-071 Trials

Introduction We report the results of a phenotypic and functional analysis of immune reconstitution in HIV(+) patients treated with allogeneic hematopoietic stem cell transplant (allo-HSCT), in comparison with HIV(+) autologous transplant (auto-HSCT) recipients, HIV(-) auto-HSCT recipients and healthy controls (HCs). Methods Blood samples were collected at days 56, 180 and 365 post-transplant from HIV(+) allo-ASCT recipients (n=17, BMT-CTN-0903/AMC-080 trial), HIV(+) auto-SCT recipients (n=36, BMT-CTN-0803/AMC-071 trial) and HIV(-) auto-SCT recipients (n=30, NCT00569309/OSU-07044 trial), and at 1 time point from 71 HCs. Five-color flow cytometry was performed on whole blood. Principal component analysis (PCA) examined global differences across 18 immune cell subsets between all subject cohorts. Wilcoxon rank-sum tests compared median absolute and proportionate cell counts. Feature importance score analysis (FIS) identified contributions of 100 immune cell populations to differences between HIV(+) cohorts and HCs. Functional responsiveness of HIV(+) allo-HSCT recipients' T cells to stimulation with CD3- and CD28-directed antibodies, NK cells to stimulation with IL-12+IL-18 and monocytes to stimulation with lipopolysaccharide (LPS) was assessed by mass cytometry on peripheral blood mononuclear cells (n=2) and compared to HCs (n=2). Results PCA showed that immunomes of HIV(+) allo-HSCT recipients and HIV(+) auto-HSCT recipients clustered together at all time points. HIV(-) auto-SCT recipients and HCs clustered together and away from the HIV(+) cohorts. FIS identified 13 cell subsets that defined the difference between HIV(+) allo-HSCT recipients (all visits) and HCs and 11 immune cell subsets that defined the difference between HIV(+) auto-HSCT recipients (all visits) and HCs; in each comparison, activated CD3+/HLA-DR+ T cells had the greatest impact on the difference between composite HIV(+) and HC immunomes. At 1 year, both HIV(+) transplant recipient cohorts had higher absolute numbers of activated T cells, effector T cells and CD8+ T cells than HCs and lower numbers of CD4+ T cells, naive T cells, and activated NK cells compared to HCs (p Conclusion Chronic HIV infection confers pro-inflammatory immune characteristics on phenotypic and functional profiling of the cellular immunome of stem cell transplant recipients, irrespective of allogeneic or autologous stem cell donor source.

Comparative Analysis of Immune Reconstitution in HIV-Positive Recipients of Allogeneic and Autologous Stem Cell Transplant on the BMT CTN 0903/AMC-080 and BMT CTN 0803/AMC-071 Trials

Introduction. Our previous flow cytometry-based comparison of HIV(+) and HIV(-) autologous hematopoietic stem cell transplant (auto-HSCT) recipient immunomes at 56, 180 and 365 days post-transplant to each other and to healthy controls (HCs) showed that both sets of auto-HSCT recipient immunomes approached HCs over time, but retained significant differences. HIV(+), but not HIV(-), auto-AHCT recipients retained pro-inflammatory features consistent with chronic HIV infection. Here, we report the results of a quantitative and functional analysis of immune reconstitution in HIV(+) patients treated with allogeneic hematopoietic stem cell transplant (allo-HSCT), in comparison with HIV(+) auto-HSCT recipients and HCs. Methods. Blood samples were collected for analysis at days 56, 180 and 365 post-transplant from HIV(+) transplant recipients and at 1 time point from HCs. Whole blood analysis was performed by five-color flow cytometry across 100 immune marker combinations. Comparisons were made between HIV(+) allo-HSCT recipients (n=17, acute myeloid leukemia, acute lymphocytic leukemia, myelodysplastic syndrome, Hodgkin and non-Hodgkin lymphoma that received myeloablative or reduced intensity conditioning on the BMT-CTN-0903/AMC-080 trial), HIV(+) auto-HSCT recipients (n=36, aggressive B cell non-Hodgkin lymphoma or Hodgkin lymphoma that received myeloablative conditioning on the BMT-CTN-0803/AMC-071 trial) and 71 HCs. Unsupervised principal component analysis (PCA) examined differences in immune cell proportions, identified by flow cytometry across 100 cell subsets at each time point. Wilcoxon rank-sum tests compared median absolute counts and median proportions of cell subsets. An independent feature importance score analysis (FIS) identified contributions of immune cell populations expressing specific immune marker combinations to the differences between HIV(+) auto-HSCT recipients, HIV(+) allo-HSCT recipients and HCs. Functional responsiveness of HIV(+) allo-HSCT recipients' T cells to stimulation with CD3- and CD28-directed antibodies, NK cells to stimulation with IL-12 and IL-18 and monocytes to stimulation with lipopolysaccharide (LPS) was assessed in a preliminary mass cytometry on peripheral blood mononuclear cells isolated at the same time points (n=2) and compared to HCs (n=2). Results. PCA showed that immunomes of HIV(+) allo-HSCT recipients and HIV(+) auto-HSCT recipients clustered together with each other, but away from HCs at all time points throughout the post-transplant year. FIS identified: 1) 13 cell subsets that defined the difference between HIV(+) allo-HSCT recipients (all visits) and HCs, and 2) 11 immune cell subsets that defined the difference between HIV(+) auto-HSCT recipients (all visits) and HCs; in both of these comparisons, activated CD3+/HLA-DR+ T cells had the greatest impact on the difference between HIV(+) and HC immunomes. At 1 year, both HIV(+) transplant recipient cohorts had higher absolute numbers of activated T cells, effector T cells and CD8+ T cells than HCs (Wilcoxon rank-sum test, p&lt;0.0031). HIV(+) autologous and allogeneic HSCT recipients also had lower numbers of CD4+ T cells, naïve T cells and activated NK cells compared to HCs (p&lt;0.0031). FIS also identified 20 immune cell subsets that defined the difference between HIV(+) autologous and allogeneic HSCT recipients immunomes at 1 year, with CD8+/CD27- effector T cell subset exerting the highest impact on the difference. Preliminary functional mass cytometry analysis of 2 HIV(+) allo-HSCT recipients and 2 HCs showed that: 1) IFNʏ production by CD8+ T cells was increased above that of HCs at all time points. 2) Expanded populations of CD4+/T-bet+ cytotoxic cells expressing granzyme B and perforin, and CD8+ cytotoxic T cells expressing granzyme B and perforin, persisted in HIV(+) allo-HSCT recipients at all time points, but not in HCs. 3) NK cells retained an ability to produce IFNʏ in response to stimulation with IL-12 and IL-18 in HIV(+) allo-SCT recipients. 4) Monocytes showed an enhanced production of TNFα in response to stimulation with LPS in HIV(+) allo-HSCT recipients compared to HCs at 1 year post-HSCT. Conclusion. Chronic HIV infection confers the pro-inflammatory immune features on the phenotypic and functional profiling of the T lymphocyte immunome of stem cell transplant recipients, irrespective of allogeneic or autologous stem cell donor source. Disclosures Devine: Bristol Myers: Other: Grant for monitoring support &amp; travel support; Kiadis Pharma: Other: Protocol development (via institution); Magenta Therapeutics: Other: Travel support for advisory board; My employer (National Marrow Donor Program) has equity interest in Magenta. Noy:Janssen: Consultancy; Medscape: Honoraria; Prime Oncology: Honoraria; NIH: Research Funding; Pharamcyclics: Research Funding; Raphael Pharma: Research Funding. Popat:Bayer: Research Funding; Incyte: Research Funding; Jazz: Consultancy. Hofmeister:Celgene: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Nektar: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Imbrium: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees. Navarro:Atara Biotherapeutics: Employment, Equity Ownership. Behbehani:Fluidigm corporation: Other: Travel funding. Lozanski:Boehringer Ingelheim: Research Funding; Beckman Coulter: Research Funding; Stemline Therapeutics Inc.: Research Funding; Genentec: Research Funding. Baiocchi:Prelude: Consultancy.

Latent Tuberculosis in Hematopoietic Stem Cell Transplantation: Diagnostic and Therapeutic Strategies to Prevent Disease Activation in an Endemic Population

Introduction Latent tuberculosis infection (LTBI) affects one third of the world population. It is well known that patients with immunodeficiency are at a higher risk of developing active tuberculosis (ATBI). Hematopoietic stem cell transplant (HSCT) recipients have an incidence of ATBI 10 to 40 times greater when compared to the general population, this being related to a higher morbidity and mortality. The aim of this study was to determine the prevalence of LTBI and incidence of ATBI after transplant in recipients and donors of HSCT living in an endemic region. Methods Retrospective single-center study that included all HSCT recipients and donors treated and followed at our Institution between February 2000 and June 2018. LTBI and ATBI were categorized according to WHO definitions. Results A total of 411 patients were included: 125 allogeneic HSCT (allo-HSCT) recipients, 167 autologous HSCT (auto-HSCT) recipients, and 119 HSCT donors. Median age of the group was 34 years (range 11-70) and 59.9% were male (n=246). Baseline diagnoses that led to HSCT were: acute leukemia in 30.9% (n=127), lymphoma in 17.3% (n=71), and monoclonal gammopathy (MG) in 10.7% (n=44) (Figure 1). Allo-HSCT donors were matched related donors (MRD) in 84.8% (n=106), matched unrelated donors (MUD) in 3.2% (n=4), haploidentical in 10.4% (n=13), and umbilical cord in 1.6% (n=2). The source of HSCT was peripheral blood (PB) in 175 patients (59.9%), bone marrow (BM) in 50 patients (17.1%), primed-BM in 65 patients (22.3%), and umbilical cord in 2 patients (0.7%). All patients were evaluated pre-HSCT with tuberculin skin test (TST) and thoracic imaging. LTBI was diagnosed in 109 patients (26.5%): 21%, 20%, and 41.2% of patients were auto-HSCT recipients, allo-HSCT recipients, and allo-donors; respectively. One-hundred and seven patients had a positive TST and two patients presented findings suggestive of LTBI on chest X-ray. Seventy-eight percent of LTBI-HSCT recipients were further evaluated with chest CT (n=29), sputum (n=26), gastric fluid (n=15), and/or urine (n=25) cultures to rule out ATBI according to treating physician's criteria. In contrast, only 42.9% (n=21) of donors were further evaluated with chest CT (n=11), sputum (n=15), gastric fluid (n=2) and/or urine (n=12) cultures. All cultures were negative at follow-up. At LTBI diagnosis 80 patients (73.3%) initiated treatment with isoniazid (INH) 300mg daily for a minimum of 6 months. Treated HSCT recipients represented 91.7% and donors were 51%. Median days of therapy received before HSCT were 76 days (range 0-732) in HSCT recipients and 48 days (range 0-401) in donors. Distribution of cases according to the patient's state of residency, excluding Mexico City, revealed an increase prevalence of cases in the southern border of the country (Figure 2). ATBI incidence at 1 year of follow-up in the cohort was 0%. Only one patient developed a pulmonary mycobacterial-related infection; however, the species identified was M. chelonae. Conclusions To our knowledge, this is the first study that evaluates the prevalence of LTBI among HSCT recipients in a Latin American country where tuberculosis is endemic. We identified a prevalence of LTBI similar to what the WHO estimates; however, the presence of lower rates in recipients compared to donors in our population suggests a negative impact of depressed humoral immunity over the TST diagnostic yield. Interestingly, we do not report any ATBI cases post-transplant; pre-transplant diagnostic strategies, as well as length of treatment may be influencing factors for these outcomes. Collaborative working groups are required to stablish the best diagnostic and therapeutic approach in order to improve ATBI-attributable morbidity and mortality in this vulnerable HSCT-patient population. Disclosures Demichelis: AMGEN: Research Funding, Speakers Bureau; Abbvie: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Shire: Speakers Bureau.