Allogeneic Stem Cell Recipients Research Articles

Mutations in human cytymegalovirus (Orthoherpesviridae: Herpesvirales: Cytomegalovirus: Cytomegalovirus humanbeta 5) UL97 gene lead to increase in viremia duration and poor antiviral response in recipients of allogeneic hematopoietic stem cells.

Human cytomegalovirus (Orthoherpesviridae: Herpesvirales: Cytomegalovirus: Cytomegalovirus humanbeta 5) (HCMV) is one of the most commonly detected viruses in recipients of allogeneic hematopoietic stem cell (allo-HSCT) transplants. However, the emergence of resistance to antiviral drugs such as ganciclovir (GCV) poses a challenge in managing these patients. This study aims to investigate the prevalence and impact of mutations in the HCMV UL97 gene associated with resistance to GCV on the course of infection among allo-HSCT patients. The study examined the association between UL97 mutations and the clinical course of HCMV infection in allo-HSCT patients. Genetic sequencing was performed to identify mutations, and their impact on viral replication and resistance to GCV was assessed. Six mutations were identified (D490A, T502A, C592G, C592F, E596G, C603W). C592G, C592F, E596G, and C603W are associated with resistance to antiviral drugs, while D490A and T502A described for the first time. When comparing patients with wild-type and those carrying the mutant variant, several parameters of peripheral blood were significantly lower in the former group. The median time to peak viral load following allo-HSCT, duration of viremia, and rate of virological response to high-dose therapy also differed significantly between the two groups. It was shown that approximately one third (4 out of 14) of allogeneic stem cell transplant recipients had mutations associated with resistance to GCV. Patients carrying the mutant variant of HCMV had longer viremia and took longer to achieve a negative virological test result after starting high-dose therapy. Performing genotyping may help make more evidence-based therapeutic decisions.

Real-Life Data on the Efficacy and Safety of Letermovir for Primary Prophylaxis of Cytomegalovirus in Allogeneic Hematopoietic Stem Cell Recipients: A Single-Center Analysis

Cytomegalovirus (CMV) reactivation is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (HSCT). Introduction of letermovir (LMV) seems to improve post-transplant outcomes, but delayed-onset CMV reactivation still remains a challenge. In this study, we report on our first experience with LMV prophylaxis in 93 CMV-seropositive adult patients receiving HSCT in our center. We retrospectively analyzed the data of 93 adult CMV-seropositive recipients receiving LMV as CMV prophylaxis after HSCT for hematological malignancies between 2019 and 2023. The starting LMV dose was 480 mg daily, reduced to 240 mg daily for those receiving cyclosporin A co-administration. CMV DNA in the blood was measured by real-time polymerase chain reaction weekly for the first 2 months after transplantation, then every other week until the end of immunosuppressive treatment. LMV was continued to day +100 or to CMV reactivation. The median recipient age at the time of transplant was 51 (range: 20-71) years. All patients received grafts from peripheral blood, mostly for acute myeloid leukemia (60%). The median time from transplantation to LMV initiation was 3 (range: 0-24) days. While 55% of patients were transplanted from matched related donors, 32% had unrelated donors and 13% underwent haploidentical HSCT. Four patients (4%) had CMV “blips” while on LMV, but the drug was continued and repeated assays were negative. Only 2 patients (2%) experienced CMV reactivation while on LMV, on days 48 and 34 after HSCT, respectively. Seven patients (7%) developed late-onset CMV reactivation after a median of 124 days after HSCT (range: 118-152 days) and they were successfully treated with ganciclovir. CMV disease was not observed. Grade III-IV acute graft-versus-host disease occurred in 6 patients (6%) during LMV treatment. LMV treatment was free of side effects. LMV prophylaxis was effective in preventing CMV reactivation with a favorable safety profile. CMV reactivation occurred mostly after LMV discontinuation; thus, extending the duration of prophylaxis beyond 100 days could be beneficial.

Efficacy of SARS-CoV-2 Vaccine Doses in Allogeneic Hemopoietic Stem Cell Recipients: A Systematic Review and Meta-Analysis.

Recipients of allogeneic hematopoietic cell transplantation (alloHCT) are at increased risk of morbidity and mortality due to COVID-19. Immune responses to SARS-CoV-2 vaccines are blunted in these profoundly immunocompromised patients. As a result, novel strategies for protection, such as additional vaccine doses (boosters), are being explored. However, data regarding the efficacy of a third dose of SARS-CoV-2 vaccine in alloHCT recipients are limited and conflicting. In this systematic review and meta-analysis, we investigated the efficacy of a third dose of SARS-CoV-2 vaccine in alloHCT recipients. The review was conducted following PRISMA guidelines, and 7 studies with 385 alloHCT recipients who received 3 vaccine doses were included. The primary outcomes assessed were the rate of seroconversion following the third dose of vaccine and the rate of seroconversion in patients who did not respond to the initial 2-dose vaccination series. The pooled humoral response rate after 3 doses of SARS-CoV-2 vaccine in alloHCT recipients was 74%. In a subgroup analysis of patients who did not respond to the initial 2-dose series, the seroconversion rate following the third vaccine dose was 49%. Notably, male patients and those with a shorter interval between alloHCT and the first vaccine dose were more likely to not respond to the third dose. In conclusion, the pooled humoral response rate of 74% following three doses of SARS-CoV-2 vaccine in alloHCT recipients highlights the potential for protection in this immunosuppressed population. Additionally, encouraging responses in nearly half of the patients who did not seroconvert with the initial 2-dose series suggest the continued utilization of additional vaccine doses until results from large prospective studies become available. These findings are critical for informing vaccination strategies in alloHCT recipients to mitigate the high mortality risk associated with COVID-19.

Antibody, cell-mediated response and infection susceptibility in allogeneic hematopoietic stem cell recipients after COVID-19 mRNA vaccination.

Patients undergoing allogeneic stem-cell transplantation (allo-SCT) have reduced responses to vaccines due to immunosuppressive status linked to GvHD prophylaxis and treatment. In our study, we compared humoral responses to anti-SARS-CoV-2 mRNA vaccine, and infection onset, according to patients and transplant features; we also evaluated cellular response in patients without seroconversion. We tested antibodies titer after second and third vaccine doses. Antibodies were detected through an immune-enzymatic assay. In a patients' subgroup without seroconversion, we tested cell-mediated responses evaluating interferon-gamma release by T-lymphocytes exposed to virus spike protein. Seroconversion rate increased from 66% at 30 days to 81% at 90 days after the second dose; it was 97% at 150 days after the third dose. We found a significant association between seroconversion after the second dose and two variables: shorter interval between allo-SCT and vaccination; ongoing immunosuppression. Twelve of 19 patients (63%) without antibodies after the second dose did not show cellular responses. Nineteen percent of patients developed SARS-CoV-2 infection after the third dose, with favorable outcome in all cases. Patients within 12 months after allo-SCT showed a significantly higher infection risk. Our study suggests that an interval shorter than 12 months between allo-SCT and first vaccine dose and/or ongoing immunosuppression were associated with humoral and cellular response deficiency after two doses. Third dose induced an increased and sustained humoral response in the majority of patients. However, patients within 1 year after allo-SCT remained at higher infection risk and may be candidate for prophylaxis with anti-SARS-CoV-2 monoclonal antibodies.

Graft failure in allogeneic hematopoietic stem cell recipients: diagnosis and treatment

Graft failure is a group of complications after allogeneic hematopoietic stem cell transplantation, which occurs according to different data up to 30%. The group of complications includes primary and secondary graft failure, primary, secondary and transient poor graft function and graft rejection. Diagnostic difficulties consist in the lack of unified diagnostic criteria accepted in the transplantation community and in the dual interpretation of these complications according to the foreign literature. The purpose of this literature review was to identify the most common criteria of different types of graft failure and determine the tactics of diagnosis and treatment. In this review we analyzed data from various literature sources, gave definitions of graft failure and poor graft function. We analyzed the literature data on the methods used to treat these conditions.

Impact of chronic graft-versus-host-disease on intensive care outcome in allogeneic hematopoietic stem cell recipients

Chronic graft-vs-host-disease (cGvHD) is the most relevant long-term complication after allogeneic stem cell transplantation (HSCT) with major impact on non-relapse mortality, but data on intensive care unit (ICU) outcome are missing. In this retrospective, multicenter study we analyzed 174 adult HSCT recipients with cGvHD requiring intensive care treatment. Skin, pulmonary, liver, and intestinal involvement were present in 76.7%, 47.1%, 38.1% and 24.1%, respectively, and a total of 63.2% had severe cGvHD. Main reasons for ICU admission were respiratory failure (69.7%) and sepsis (34.3%). Hospital- and 3-year OS rates were 51.7% and 28.6%, respectively. Global severity of cGvHD did not impact short- and long-term survival. However, patients with severe liver cGvHD or the overlap subtype had a reduced hospital survival, while severe pulmonary cGvHD was associated with worse long-term survival. In multivariate analysis need for invasive ventilation (HR 1.08 (95% CI 1.02–1.14)) or hemodialysis (HR 1.73 (95% CI 1.14–2.62)) and <1 year since HSCT (HR 1.56 (95% CI 1.03–2.39)) were independently associated with a poorer survival. While the global severity of cGvHD does not per se affect patients’ survival after intensive care treatment, pre-existing severe hepatic, intestinal or pulmonary cGvHD is associated with worse outcomes.

Allogeneic Stem Cell Cryopreservation Is Associated with Equivalent Survival and Relapse Rates with Lower Rate of Severe Chronic Gvhd

The ongoing COVID-19 pandemic continues to raise challenges for safe administration of allogeneic hematopoietic stem cell transplantation (allo-HSCT). From March to August 2020, unrelated donor (URD) peripheral blood stem cell (PBSC) products were shipped to central national hubs and cryopreserved either at the site of collection or infusion, a shift from the traditional practice of infusing fresh stem cells. The National Marrow Donor Program (NMDP) instituted this mandate due to uncertainty around international transportation of stem cells as well as a fail-safe to prevent interruptions to a planned transplant if a donor contracted COVID-19 after the recipient started conditioning chemotherapy. We previously published our single institution experience demonstrating equivalent short-term clinical outcomes (overall survival [OS], progression free survival [PFS], relapse, and non-relapse mortality [NRM]) between adult recipients of fresh vs cryopreserved allogeneic stem cells (median follow up time 16 months [fresh] vs 8 months [cryopreserved]) (PMID: 34581754). We also demonstrated lower T-cell chimerism at day 30 and 100 after receipt of cryopreserved grafts. There is a paucity of data evaluating longer term outcomes of patients receiving cryopreserved stem cells compared to fresh. Currently there is variability among donation and transplant centers around the practice of cryopreservation prior to allo-HSCT. With ongoing surges of COVID-19 and evolution of new variants, the risk of donors or recipients contracting COVID-19 leading to delays or disruptions in planned allo-HSCT remains high. In January 2022 with the rise of the Omicron variant of COVID-19, the NMDP reinstated the cryopreservation recommendation. Anecdotal reports indicate multiple recent instances of a planned URD testing positive for COVID-19 after conditioning chemotherapy had started but before stem cell harvest, raising the potential for severe deleterious outcomes in the intended transplant recipient. Given the unremitting COVID-19 surges three years into the pandemic and continued uncertainty around longer-term survival and relapse rates of allo-HSCT using cryopreserved stem cells, we reanalyzed our prior cohort and added 116 additional patients (40 cryopreserved, 76 fresh) with at least 1-year follow up for a total of 141 and 279 patients receiving cryopreserved versus fresh (respectively) URD PBSCs between January 1, 2019, and July 31, 2021. The cohorts had similar baseline characteristics including donor/recipient age/sex, disease, and conditioning regimen/intensity. Patients receiving cryopreserved cells were more likely to receive post-transplant cyclophosphamide as part of the graft versus host disease (GVHD) prophylaxis regimen (24% vs 15%, p=0.015). Median follow-up time among survivors in this cohort was 22 months (range, 4-41 months). Two-year OS was not different in patients receiving fresh versus cryopreserved stem cells (63% vs 63%, p=0.73) (Figure 1A). Two-year PFS was also similar (57% for fresh, 52% for cryopreserved, p=0.27) (Figure 1A). Relapse (36% vs 30%, p=0.17) and NRM (12% vs 13%, p=0.79) at two years were comparable between patients receiving fresh versus cryopreserved stem cells (Figure 1B). In total, 8 patients died of COVID-19 in this cohort (4 fresh, 3 cryopreserved). Cumulative incidence of moderate/severe chronic GVHD (cGVHD) was higher in patients receiving fresh stem cells versus cryopreserved (24% vs 9%, p=0.0003). Whereas cryopreservation was associated with lower T-cell chimerism early after transplant, by 1-year post-transplant, T-cell chimerism was not different (2% vs 5% of fresh vs cryopreserved patients with T-cell chimerism <75% at 1 year, p=0.14). However, Day 30 T-cell chimerism <75% was associated with a reduction in OS and PFS regardless of cryopreservation of stem cells (data not shown). As the COVID-19 pandemic continues with frequent surges in case numbers and rapid viral evolution, the risk for interruptions in life-saving allo-HSCT therapies remains high. Our data show that allo-HSCT with cryopreserved URD PBSCs results in similar OS, PFS, relapse rates, and NRM at 2 years post-transplantation. We found that cryopreservation is associated with lower 1-year cumulative incidence of moderate/severe cGVHD without compromise in OS. While this is an intriguing finding, larger multicenter analyses are needed to confirm these observations. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Single Center Analysis of Hematopoietic Recovery in Patients Undergoing Allogeneic BMT with Suboptimal CD34+ Doses

Background: Allogeneic stem cell transplant (allo-SCT) is the only curative treatment for many hematologic malignancies. Stem cells can be collected from bone marrow, peripheral blood, or cord blood. Peripheral blood is the most common utilized source due to its convenience and the ability to collect high numbers of stem cells, but studies suggest that bone marrow offers certain advantages over peripheral blood, especially lower rates of graft-vs-host disease (Holtick et. al. Cochrane 2014), leading to higher survival in patients with nonmalignant disorders . The ideal cell dose for SCT is 2 x 106 cells/kg CD34 cells. However, in cases of bone marrow graft, if a suboptimal cell dose is collected, it is often not feasible to repeat extraction. This is especially difficult for minority ethnic groups who already face systemic barriers to care. Our goal for this study was to assess the correlation of CD34 dose to hematopoietic recovery in a minority-rich population of fresh marrow allogeneic stem cell recipients. Prior studies have also suggested that the cell dosing for transplant should be calculated by ideal body weight (IBW) rather than the standard actual body weight (ABW) (Cilley et. al. Bone Marrow Transplantation 2004). We assessed the correlation of recovery for ABW vs IBW as well. Methods: From 2012-2022, eighteen patients were identified in the Montefiore health system who received a bone marrow graft for allo-SCT with suboptimal CD34 doses. Alongside CD34 dose, an additional predictor evaluated was total nucleated cell (TNC) dose. ABW-based and IBW-based doses were calculated for both CD34 and TNC doses. Several outcomes were tracked for the eighteen patients, including "Days to WBC 1000 cells/μL", "Days to ANC 500 cells/μL ", and "Days to Plt≥20,000 cells/μL." The relationship between cell doses (ABW and IBW-based) and outcomes were evaluated independently through calculation of Spearman's correlation. Analysis and modeling were performed in RStudio 4.1.2. Results: AML and NHL patients made up the largest proportion of the sample (7/18 and 5/18) (Table 1). The median ABW-based CD34 dose (0.530 x 106 CD34 cells/kg) was nearly four times smaller than the standard of 2 x 106 cells/kg CD34 cells. Fifteen of 18 patients achieved reconstitution goals. Of the three patients who did not, one had persistent disease at the time of transplant and developed multiorgan failure dying within 17 days prior to hematopoietic recovery. Another died at day 58 without any platelet recovery. A third maintained platelets above 20,000 cells/μL throughout transplant. Assessing ABW-based CD34 dosing and IBW-based CD34 dosing as independent predictors, none of the outcomes, were significantly correlated (P > 0.05) (Figure 2). However, the Spearman's correlation coefficients were consistently of larger magnitude for IBW-based CD34 dosing than for ABW-based CD34 dosing for all three outcomes. Assessing ABW-based TNC dosing and IBW-based TNC dosing as independent predictors yielded no significant correlation. Conclusion: Studies suggest that there are benefits to bone marrow grafts over that of peripheral stem cell grafts. However, bone marrow harvesting is a process that is not easily repeated in cases where doses are inadequate, especially if the recipient has already undergone conditioning. We reviewed 18 cases of allo-SCTs performed at a single center with suboptimal CD34+ doses. In most cases, hematopoietic reconstitution was achieved. In our cohort of patients with suboptimal CD34+ doses in allo-BM SCTs, we noted no significant correlation between the dosages and outcomes for hematopoietic reconstitution. These results suggest there may be utility in taking a more liberal approach to standards for bone marrow graft doses, but this requires further study, and a much larger sample size. Additionally, we looked at CD34 dosing based on ABW versus IBW and noted consistent increases in magnitude for the Spearman Correlation's. Given the small sample evaluated, it is worth looking at this further with larger samples to see if dosing for bone marrow harvest by IBW may be more correlated with hematopoietic reconstitution in allogeneic SCT than dosing by ABW. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Letermovir Prophylaxis for CMV Reactivation in Allogeneic Stem Cell Recipients: A Retrospective Single Center Analysis.

Cytomegalovirus (CMV) reactivation is one of the most clinically significant complications in allogeneic stem cell recipients and a frequent cause for transplantation related mortality. Letermovir is a newly available and recently approved drug for CMV prophylaxis. In a retrospective single center analysis, we investigated the benefit of letermovir as CMV prophylaxis in allogeneic stem cell recipients. We included 48 CMV-seropositive transplant recipients from January 2017 to August 2020 from our department. We compared the rate of CMV reactivation in patients who received letermovir as prophylaxis from day 0 after allogeneic stem cell transplantation (alloSCT) with a control group that did not receive CMV prophylaxis. The primary endpoint was CMV reactivation and was defined as an increase of CMV copies over 1250 Ul/ml in the peripheral blood; secondary endpoints were overall survival (OS) up to 180 days, engraftment and all-cause mortality. We included 21 patients in the control group and 27 patients in the letermovir group. Letermovir treatment led to a significantly reduced incidence of CMV reactivation after alloSCT (33.3% in the letermovir group versus 76.2% in the control group, p<0.001). The OS at day 180 was 80.9% in the control group versus 92.6% in the letermovir group (p<0.05). The median duration of letermovir prophylaxis was 192±104 days. Our results indicate that letermovir prophylaxis is associated with a significant lower risk of CMV reactivation and improved overall survival in CMV-seropositive stem cell recipients. Moreover, a prolonged use of letermovir prophylaxis might be a survival benefit.

Intensive care of life-threatening complications in allogeneic hematopoietic stem cell recipients

Introduction. Life-threatening complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT) can have a significant influence on the short-term and long-term prognosis in recipients of hematopoietic stem cells (allo-HSCs).Aim — to determine the life-threatening complications and the risk factors of their occurrence and to evaluate the short-term and long-term prognosis in critically ill allo-HSCs recipients.Materials and methods. All patients over the age of 18 who underwent allo-HSCT from 01.01.2012 to 01.01.2022 were included in the retrospective study. Patients were divided into two groups: those who required intensive care unit (ICU) admission and those who did not require ICU admission. In the group of ICU admitted allo-HSCs recipients the reasons of ICU admission, timing of their occurrence and the results of life support were recorded. The risk factors of life-threatening complications occurrence and prognostic factors were analyzed.Results. In total, 174 (26.7 %) of 652 allo-HSCs recipients required ICU admission. The risk factors of life-threatening complications were: allo-HSCT in patients with acute leukemia who did not achieve complete remission (hazard ratio (HR) = 2.10; 95 % confidence interval (95% CI): 1.28–3.44; p = 0.003), allo-HSCT without conditioning in patients with hematopoietic aplasia after chemotherapy (HR = 30.63; 95% CI: 8.787–107.04; p &lt; 0.001), graft failure (HR = 2.51; 95% CI: 1.58–3.97; p &lt; 0.001) and poor graft function (HR = 2.85; 95% CI: 1.6–5.05; p &lt; 0.001), acute graft versus host disease (GVHD) (HR = 2.04; 95% CI: 1.459–2.85; p &lt; 0.001). The main reasons of ICU admission were sepsis and/or septic shock (SS) (27.9 %), acute respiratory failure (23.9 %), neurological disorders (17.7 %). The type and periods of allo-HSCT influenced the timing and structure of critical illnesses. The ICU mortality rate after all ICU admissions and readmissions was 59.8 % with a maximum follow-up of 9 years. The risk factors of ICU mortality were the occurrence of critical conditions after +30 days of allo-HSCT, the need for mechanical ventilation and vasopressors. The overall survival (OS) rate of ICU admitted allo-HSCs recipients was 13.8 %. Sepsis and/or SS that occurred in the early phase after allo-HSCT were characterized by the most favorable long-term outcome (OS — 43.8 %) among all complications of the peritransplantation period. The OS of patients discharged from the ICU was worse than OS of patients who did not require ICU admission (34.6 % vs. 58.3 %; p = 0.0013). Conclusion. Transplant centers should have a specialized ICU because more than a quarter of allo-HSCT recipients experience life-threatening complications at different allo-HSCT periods. Sepsis and SS occurring in the early pre-engraftment phase had a more favorable prognosis than other life-threatening complications. The long-term outcomes in allo-HSCs recipients who survived critical illness are worse than in recipients who did not require ICU admission.

Strong SARS-CoV-2 T-Cell Responses after One or Two COVID-19 Vaccine Boosters in Allogeneic Hematopoietic Stem Cell Recipients.

A full exploration of immune responses is deserved after anti-SARS-CoV-2 vaccination and boosters, especially in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although several reports indicate successful humoral responses in such patients, the literature is scarce on cellular specific immunity. Here, both B- (antibodies) and T-cell responses were explored after one (V3 n = 40) or two (V4 n = 12) BNT162b2 mRNA vaccine boosters in 52 allo-HSCT recipients at a median of 755 days post-transplant (<1 year n = 9). Results were compared with those of 12 controls who had received only one booster (BNT162b2 n = 6; mRNA-1273 n = 6). All controls developed protective antibody levels (>250 BAU/mL) and anti-spike T-cell responses. Similarly, 81% of the patients developed protective antibody levels, without difference between V3 and V4 (82.5% vs. 75%, p = 0.63), and 85% displayed T-cell responses. The median frequency of anti-spike T cells did not differ either between controls or the whole cohort of patients, although it was significantly lower for V3 (but not V4) patients. COVID-19 infections were solely observed in individuals having received only one booster. These results indicate that four vaccine injections help to achieve a satisfactory level of both humoral and cellular immune protection in allo-HSCT patients.

Role of the intensive care in allogeneic hematopoietic stem cell transplantation

Introduction. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is often complicated by life-threatening conditions.Aim — an analysis of the life-threatening complications in recipients of allogeneic hematopoietic stem cells (allo-HSCs)Main findings. From 10 to 50 % of allo-HSC recipients need to be admitted to the intensive care unit (ICU) due to the development of life-threatening complications. The reasons for ICU admission are acute respiratory failure, sepsis, graft-versus-host disease, veno-occlusive disease, thrombotic microangiopathy, cytokine release syndrome, engraftment syndrome, etc. Conditioning regimen, donor type, stem cell source, underlying disease state and patient comorbidity are the risk factors associated with development of life-threatening conditions. The main prognostic factors of unfavorable ICU outcomes in allo-HSC recipients are the severity of multiple organ dysfunction and the need for organ support.

Systemic antifungal strategies in allogeneic hematopoietic stem cell recipients hospitalized in french hematology units: a post-hoc analysis of the cross-sectional observational AFHEM study\ufeff

BackgroundInvasive fungal diseases (IFD) remain a major complication of allogeneic hematopoietic stem cell transplantation (alloHSCT) and are associated with high mortality rates in patients receiving alloHSCT. Antifungal prophylaxis is increasingly being used in the management of IFDs in patients receiving alloHSCT.MethodsA post-hoc analysis of the cross-sectional observational AFHEM study was carried out to describe the use of antifungal drugs in real-life clinical practice in alloHSCT recipients hospitalized in French hematological units.ResultsA total of 147 alloHSCT recipients were enrolled; most were adults (n = 135; 92%) and had received alloHSCT < 6 months prior to enrollment (n = 123; 84%). Overall, 119 (81%) patients received a systemic antifungal therapy; of these, 95 (80%) patients received antifungal prophylaxis. Rates of patients receiving systemic antifungal treatment were similar irrespective of transplant time, neutropenic, and graft-versus-host disease status. Among patients on systemic antifungal treatment, 83 (70%) received an azole, 22 (18%) received an echinocandin, and 16 (13%) received a polyene.ConclusionsThis work provides evidence of the antifungal strategies used in alloHSCT recipients hospitalized in French hematological units. Unlike earlier studies, the AFHEM study showed that prophylaxis appears to be the leading antifungal strategy used in alloHSCT recipients in France.

SARS-CoV-2 T-Cell Responses in Allogeneic Hematopoietic Stem Cell Recipients following Two Doses of BNT162b2 mRNA Vaccine.

Background: At variance to humoral responses, cellular immunity after anti-SARS-CoV-2 vaccines has been poorly explored in recipients of allogeneic hematopoietic stem-cell transplantation (Allo-HSCT), especially within the first post-transplant years where immunosuppression is more profound and harmful. Methods: SARS-CoV-2 Spike protein-specific T-cell responses were explored after two doses of BNT162b2 mRNA vaccine in 45 Allo-HSCT recipients with a median time from transplant of less than 2 years by using INF-γ ELISPOT assay and flow-cytometry enumeration of CD4+ and CD8+ T lymphocytes with intracellular cytokine production of IFN-γ and TNF-α. Results: A strong TNF-α+ response from SARS-CoV-2-specific CD4+ T-cells was detected in a majority of humoral responders (89%) as well as in a consistent population of non-humoral responders (40%). Conclusions: T-cells are likely to participate in protection against COVID-19 viral infection, even in the absence of detectable antibody response, especially in the first years post-transplant in Allo-HSCT recipients.

Factors Associated With Cytomegalovirus Infection in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Prospective Single-Center Study.

The human cytomegalovirus is a notorious pathogen in the pediatric transplant setting. Although studies on factors in complicity with cytomegalovirus infection abound, the roles of age, sex, allogeneic hematopoietic stem cell transplant modality, and type of underlying disease (malignant vs nonmalignant) with regard to cytomegalovirus infection and viral load in children are seldom explored. Our aim was to examine the significance of these factors on cytomegalovirus infection and viral load in Serbian pediatric recipients of allogeneic hematopoietic stem cell transplant. Thirty-two pediatric recipients of allogeneic hematopoietic stem cell transplant to treat various malignant and nonmalignant disorders were prospectively monitored for cytomegalovirus infection. The real-time quantitative polymerase chain reaction was used for pathogen detection and quantitation. Demographic and virologic parameters were statistically analyzed with SPSS statistics software (version 20). Cytomegalovirus DNA was detected in 23 patients (71.9%). Infection occurred significantly more often (P = .015) in patients with haploidentical donors. The opposite was noted for matched sibling grafts (P = .006). Viral load was higher in female patients (P = .041) and children with malignant diseases (P = .019).There was no significant relationship between viral infection or load and medical complications. Transplant recipients presented with a high incidence of cytomegalovirus viremia. The modality of allogeneic hematopoietic stem cell transplant was associated with the frequency of cytomegalovirus infection. Age, sex, type of underlying disease, and medically relevant events were not conducive to occurrences of viremia. Notably, we observed substantial viral loads in female patients and patients with neoplastic diseases. Studies comprising larger populations are needed to better understand these results.

Differences of Human Cytomegalovirus Strains in Recipients of Allogeneic Hematopoietic Stem Cells before and after Transplantation

Background. Human cytomegalovirus (HCMV) is a ubiquitous viral infection of worldwide distribution. This virus is the most significant infectious cause of congenital disease, an important opportunist in the immunocompromised hosts, such as allogeneic hematopoietic stem cells transplantation (allo-HSCT) recipients (Mokarski E.S.,2013). If seropositive recipient develops HCMV infection after allo-HSCT, it is usually unknown whether it is a reactivation of endogenous HCMV or a reinfection by a new exogenous HCMV strain. The impact of genetic diversity of HCMV on its pathogenesis has not been well evaluated by now. However, the emerging data indicate a possible correlation: the viral load and the course of the infection were different in AIDS patients with different HCMV genotypes (Renzette, 2015). The estimation of a possible link between viral genotype and probability of HCMV infection occurrence is relevant. Very little data on difference in HCMV genotypes within one patient before and after allo-HSCT is available.The aim. The aim of this study was the identification of difference in HCMV UL139 gene sequences before and after the allo-HSCT.Materials and Methods. Patients: 13 allo-HSCT recipients (5 ALL, 3 AML, 3 CML, 1 AA, 1 lymphoma of the mantle) were enrolled in the study, male/female 6/7; median age was 27 (22-49) years. Patients' blood samples were collected within 6 month before and 6 month after transplantation and tested for the HCMV DNA by PCR. Positive samples were sequenced by Sanger inside the UL139 (putative membrane gp gene) region for genotyping. Sequences within one patient before and after transplantation were compared by BLAST (Basic Local Alignment Search Tool) software.Results and discussion. Sequencing was successfully completed only in samples of 7 patients (pts), probably due to low concentration of the viral DNA in the samples or other technical issues. The comparison of sequences showed (see table) that 3 out of 7 pts had reactivation of endogenous virus, because sequences exhibited 100% match. Another 2 out of 7 patients' sequences showed about 88% match. This indicates change in genotype to phylogenetically closest one. The rest 2 pts did not show any similarity in sequences at all which definitely points to reinfection after allo-HSCT. Data obtained are similar to a recent study by Zawilinska (Zawilinska B, 2016), which appeals that reinfection occurs slightly more often than reactivation. Data analys showed that reactivation was detected in patients with AML, reinfection in patients with ALL. Average period before reactivation occurrence was 27 days and before reinfection occurrence - 111 days. Statistical reliability cannot be obtained due to patients' number paucity. The genotyping of patients' HCMV by comparison of sequences with known genotypes of the UL139 gene from GenBank® revealed that before transplantation HCMV genotype in 3 patients had a strong resemblance to genotype 2, another 2 patients had genotype close to the genotype 5, and 1 patient had genotype 1. After transplantation genotype 2 became dominant and was identified in 6 out of 7 patients (see table).Conclusions. The conducted study shows that HCMV infection after allo-HSCT may be the result of both reactivation of endogenous virus and reinfection by exogenous strain. Reactivation was detected in patients with AML only, reinfection - in patients with ALL only. Reactivation developed earlier than reinfection (27 days versus 111 days). The chosen method allowed us to detect several mononucleotide substitutions in sequences, what can be useful in cases when no evident change of genotype happened after allo-HSCT. There are several possible explanations of the occurrence of reinfection: possible transmission from the outer environment or reactivation of a minor genotype if 2 or more HCMV genotypes originally had taken place. Further studies are required for more reliable conclusions. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Bone marrow transplantation patients in the intensive care unit

Die allogene hämatopoetische Stammzelltransplantation (HSZT) stellt für viele Patienten mit maligner, aber auch nichtmaligner hämatologischer Grunderkrankung die einzige Chance auf Heilung dar. Dies gilt insbesondere für Patienten, die genetisch bedingt ein hohes Rezidivrisiko haben oder sich refraktär auf eine konventionelle Therapie zeigen. Durch die allogene HSZT eröffnet sich für diese Patienten eine Langzeitperspektive bei ansonsten infauster Prognose. Diese Therapieform ist jedoch mit einer nicht unerheblichen Morbidität und Mortalität assoziiert. Ein Teil der Patienten wird aufgrund von infektiösen, immunologischen und/oder toxischen Komplikationen intensivpflichtig. Nach wie vor ist unklar, ob Patienten in solchen klinischen Situationen von einer Intensivtherapie mit mechanischer Beatmung und Nierenersatztherapie profitieren, da die Mortalität der Betroffenen hoch ist. Diese Arbeit beschreibt die wichtigsten Komplikationen und mögliche Behandlungsstrategien von allogen blutstammzelltransplantierten Patienten auf der Intensivstation.

Cytomegalovirus after allogeneic hematopoietic stem cell transplantation: reactivation or reinfection?

Objective. To determine type of cytomegalovirus (CMV) infection (reactivation of a virus strain that was present before transplantation or re-infection with another virus strain) in allogeneic hematopoietic stem cell recipients by sequencing. Materials and Methods. Clinical and laboratory data of 179 recipients of allogeneic hematopoietic stem cells collected from 2014 to 2018 were analyzed for CMV DNA in clinical specimens before and after transplantation. A total of 14 patients (28 samples) were included in the study. The CMV UL139 gene encoding viral glycoprotein was chosen for virus genotyping and sequence alignment. The primers complementary to its conservative sites were used. The resulting DNA sequence was analyzed using nucleotide BLAST software (https://blast.ncbi.nlm.nih.gov/Blast.cgi) and Genome compiler (https://designer.genomecompiler.com). The type of infection was determined by comparing DNA sequences before and after transplantation. Results. All enrolled patients were anti-CMV-positive prior to transplantation, which indicates the presence of CMV infection. Therefore, none of the patients had a primary infection as a result of transplantation. Of 14 patients, high percentage of sequence alignment (~100%) was observed in 8 patients. For the other 6 patients, substantial differences in sequences which indicate the different genotypes and the different type of infection were found. However, there was no statistically significant difference in the time to viral DNA appearance after transplantation in patients with re-infection and reactivation (p &gt; 0.05), nor was there a statistically significant correlation between the type of infection (reactivation/re-infection) and the main diagnosis or transfusion load. Conclusions. Reactivation of the previously registered viral strain and re-infection with another viral strain were equally probable (8 vs. 6 cases). There were no associations between the main diagnosis and the type of infection (reactivation/re-infection) possibly due to a small sample size. Time to post-transplantation CMV DNA detection in blood was longer for re-infection (median of 69.5 days) compared to reactivation (median of 27 days), but this difference was also non-statistically significant. In addition, there was no significant contribution of blood transfusion burden to the type of CMV infection, which may suggest the donor blood is not a source of the different strains.

High Dose Valaciclovir As CMV Prophylaxis in Allogeneic Hematopoietic Stem Cell Recipients at High Risk of CMV Reactivation

Background Cytomegalovirus (CMV) is a common, potentially devastating complication of allogeneic haematopoietic stem cell transplantation (alloHSCT). Universal antiviral prophylaxis strategies including letermovir are effective, but unsubsidised in Australia. Prophylactic ganciclovir or valganciclovir are challenging due to myelotoxicity. Valaciclovir demonstrates anti-CMV activity in high doses, but little current data explore prophylaxis in the alloHSCT setting, particularly in haploidentical transplantation. We aimed to evaluate the clinical efficacy and tolerability of high dose valaciclovir (high dose VALA) as CMV prophylaxis in high risk patients undergoing alloHSCT. Methods This study was completed at the Royal Melbourne Hospital, Melbourne Australia. We performed a retrospective analysis of alloHSCT recipients at high risk of CMV reactivation (defined as recipient and/or donor CMV seropositivity, and undergoing T-cell depletion, haploidentical or umbilical cord stem cell transplantation). Patients transplanted between July 2018 - June 2019, treated with high dose VALA (2g TDS) from day +7 to +100 and beyond were compared to a historical cohort (transplanted between July 2017 - June 2018) on standard dose valaciclovir (std dose VALA) (500mg BD until engraftment then 500mg daily). We compared the rates and time to reach a CMV threshold of 400 IU/ml, at which point pre-emptive CMV therapy was commenced. Tolerability was also evaluated. Results Patient demographics are described in Table 1. Of the standard dose VALA cohort, (median follow-up 259 days), 23/31 (74%) developed a viral load &amp;gt;400 IU/mL, requiring pre-emptive CMV therapy. None had CMV disease. Median time to viral load &amp;gt;400 IU/mL was 39 days (range 13 - 68). Of the high dose VALA cohort (median follow-up 209 days), 11/25 (44%) developed a viral load &amp;gt;400 IU/mL, requiring pre-emptive CMV therapy. Of these 11 cases, 7 patients had viral load &amp;gt;400 IU/mL while on high dose VALA prior to D+100, 3 patients had ceased high dose VALA prior to D+100 due to intolerance and in 1 patient this occurred post D+100 while on high dose VALA. One patient developed CMV (gut) disease following early cessation of high dose VALA, whilst on standard dose VALA. Median time to reactivation &amp;gt;400 IU/mL was 64 days (range 26-170). Time to reactivation &amp;gt;400 IU/ml was significantly different between the standard vs high dose VALA cohorts (mean ± SEM; 37.9 ± 2.7 vs 67.8 ± 11.3 days, **p=0.0015). Median duration of high dose VALA prophylaxis was 50 days (range 11-288). Seven (28%) patients continued high dose VALA to day +100 and beyond. Intolerance led to early cessation in 10 (40%) patients (acute kidney injury, n=6; cytopenia, n=3; both, n=1). Other patients ceased due to requirement for definitive CMV therapy (n=6) and unclear reasons (n=2). Conclusions In high risk alloHSCT recipients, high dose VALA is an effective CMV prophylactic strategy resulting in lower CMV reactivation rates, and delays CMV reactivation. This may reduce requirements for myelotoxic CMV treatment during the early post-engraftment period and need for inpatient admission. CMV infection following high dose VALA cessation remains a risk, particularly when dose reductions have occurred due to toxicity, and intolerance and ongoing monitoring is required. Treatment tolerability remains a limitation. Disclosures No relevant conflicts of interest to declare. OffLabel Disclosure: Valaciclovir, for CMV prophylaxis

Bronchiolitis and Bronchiolar Disorders.

Bronchioles are noncartilaginous small airways with internal diameter of 2 mm or less, located from approximately the eighth generation of purely air conducting airways (membranous bronchioles) down to the terminal bronchioles (the smallest airways without alveoli) and respiratory bronchioles (which communicate directly with alveolar ducts and are in the range of 0.5 mm or less in diameter). Bronchiolar injury, inflammation, and fibrosis may occur in myriad disorders including connective tissue diseases, inflammatory bowel diseases, lung transplant allograft rejection, graft versus host disease in allogeneic stem cell recipients, neuroendocrine cell hyperplasia, infections, drug toxicity (e.g., penicillamine, busulfan), inhalation injury (e.g., cigarette smoke, nylon flock, mineral dusts, hard metals, Sauropus androgynous); idiopathic, common variable immunodeficiency disorder, and a host of other disorders or insults. The spectrum of bronchiolar disorders is wide, ranging from asymptomatic to fatal obliterative bronchiolitis. In this review, we discuss the salient clinical, radiographic, and histological features of these diverse bronchiolar disorders, and discuss a management approach.