Antilymphocyte Globulin Research Articles

The long-term outcomes and safety of severe aplastic anemia treated with porcine antilymphocyte globulin plus cyclosporine, with or without thrombopoietin receptor agonists: a double-center retrospective study

ABSTRACT Background Porcine antilymphocyte globulin (p-ALG) combined with cyclosporine (CsA) has been commonly used for severe aplastic anemia (SAA) patients, but few studies on the combination of p-ALG and thrombopoietin receptor agonist (TPO-RA). Research design and methods We retrospectively analyzed the data of 85 people with diagnosed SAA who underwent p-ALG plus CsA, with or without TPO-RA from 2014 to 2023. Results The overall response rates were 55.3% and 65.9% at 3 and 6 months, and the TPO-RA group were 66.7% and 72.3% at 3 and 6 months, without TPO-RA group were 27.8% and 55.6%. In multivariate analysis, baseline platelet count of > 10 × 109/L was a simple predictor of favorable response at 6 months (p = 0.015). The median follow-up time for all patients was 39 months (range 0.4 ~ 104), the 5-year overall survival (OS) rate was 90.6% [95% CI = 82.1–95.2%], and the failure-free survival (FFS) rate was 68.9% [95% CI = 56.6–78.4%]. Having hematologic responses in 6 months was an independent positive predictor for FFS (p = 0.000). Twelve patients (14.1%) suffered from serum sickness, and 9.5% of patients had mild hepatic impairment. Conclusions p-ALG along with CsA is an effective choice for patients with SAA. p-ALG combined with TPO-RA may contribute to the early restoration of hematopoiesis.

First-in-human Study With LIS1, a Next-generation Porcine Low Immunogenicity Antilymphocyte Immunoglobulin in Kidney Transplantation.

Polyclonal rabbit antithymocyte globulins (ATGs) are commonly used in organ transplantation as induction. Anti- N -glycolylneuraminic acid carbohydrate antibodies which develop in response to rabbit carbohydrate antigens might lead to unwanted systemic inflammation. LIS1, the first new generation of antilymphocyte globulins (ALGs) derived from double knockout swine, lacking carbohydrate xenoantigens was already tested in nonhuman primates and rodent models. This open-label, single-site, dose escalation, first-in-human, phase 1 study evaluated the safety, T cell depletion, pharmacokinetics, and pharmacodynamics of LIS1. In an ascending dose cohort (n = 5), a primary kidney transplant recipient at low immunologic risk (panel reactive antibody [PRA] < 20%), received LIS1 for 5 d at either 0.6, 1, 3, 6, or 8 mg/kg. After each patient completed treatment, the data safety monitoring board approved respective dose escalation. In the therapeutic dose cohort (n = 5) in patients with PRA <50% without donor specific antibodies, 2 patients received 8 mg/kg and 3 patients 10 mg/kg. CD3 + T cell depletion <100/mm 3 at day 2 was observed in all patients who received 6, 8, and 10 mg/kg of LIS1. The terminal half-life of LIS1 was 33.7 d with linearity in its disposition. Lymphocyte repopulation was fast and pretransplant lymphocyte subpopulation counts recovered within 2-4 wk. LIS1 was well tolerated, neither cytokine release syndrome nor severe thrombocytopenia or leukopenia were noticed. Antibodies to LIS1 were not detected. In this first-in-human trial, genome-edited swine-derived polyclonal LIS1 ALG was well tolerated, did not elicit antidrug antibodies, and caused time-limited T cell depletion in low- and medium-risk kidney transplant recipients.

Porcine Anti-Lymphocyte Globulin, Cyclosporine A Plus Thrombopoietin Receptor Agonists Achieved Similar Efficacy and Survival Compared to Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Aplastic Anemia.

Immunosuppressive therapy (IST) with horse or rabbit anti-human thymocyte immunoglobulin (h-/r-ATG) and hematopoietic stem cell transplantation (HSCT) are two baseline treatments for severe aplastic anemia (SAA) and transfusion-dependent non-severe aplastic anemia (TD-NSAA) patients. Addition of thrombopoietin receptor agonists (TPO-RAs) to standard IST therapy (h-/r-ATG) has greatly improved the survival of SAA, whereas porcine anti-lymphocyte globulin (p-ALG) combined with TPO-RAs still had a matter of debate. We retrospectively compared the data of 48 AA patients in our center between 2020 and 2022, 23 AA patients received with p-ALG ± TPO-RAs, 25 AA patients underwent matched sibling donor (MSD-) or haploidentical (haplo-) HSCT. For patients in the HSCT group, the ORR was 90.9% which was significantly higher than that in the IST±TPO-RAs group (45.5%, P = 0.001) at 3 months; moreover, patients who underwent HSCT achieved faster transfusion independence, better CR rate, shorter time of recovery normal blood routine, and the percentage of normal blood routine (all P < 0.05) compared with IST±TPO-RAs group. However, the ORR were similary at 6 months in the two groups (95.5% vs 81.8% P = 0.342), with a median follow up of 19.8 months (range, 0.3-38.2 months), the 2-year FFS and OS in the two cohorts has no different. Subgroup analysis further indicated that the 2-year FFS and OS were similar between IST+TPO-RAs and haplo-HSCT subgroups, as well as in IST+TPO-RAs and MSD-HSCT cohorts. Moreover, the first-time hospitalizations were much more expensive in the HSCT group than in the IST±TPO-RAs group (402 756 vs. 292 902 yuan, P = 0.002). P-ALG-based-IST±TPO-RAs is a good treatment option with similar FFS and OS compared to allo- HSCT for AA patients without the opportunity of HSCT.

Porcine antilymphocyte globulin versus rabbit antithymocyte globulin for intensive immunosuppressive therapy of acquired aplastic anemia: A meta-analysis and systematic review.

Several studies have reported that porcine antilymphocyte globulin (pALG) has a significant effect on aplastic anemia (AA), but their conclusions are inconsistent. To objectively evaluate its efficacy and safety, a meta-analysis was conducted. We systematically searched the relevant literature on pALG vs. rabbit antithymocyte globulin (rATG) as the first-line treatment in AA patients until August 31, 2022, in electronic databases: PubMed, Cochrane Library, Web of Science, etc. Two researchers independently extracted data and evaluated the quality of the study. Stata 14.0 was used for statistical analysis. 50 studies were included in the analysis. The overall responses at 3, 6, and 12 months between the pALG group and rATG group were equivalent. We analyzed early mortality, total mortality, relapse rates, and 5-year survival after the administration of pALG or rATG, and there was no significant difference between the pALG and rATG groups. In our study, the incidence of infection in the pALG group was better than that in the rATG group, OR=0.63, 95% CI (0.44-0.88), p=0.008, which showed a statistically significant difference. The efficacy of pALG in AA patients is equivalent to that of rATG. rATG was associated with a significantly higher incidence rate of infection than pALG.

Effectiveness of invivo T-cell-depleted regimen containing porcine anti-lymphocyte globulin or rabbit anti-thymocyte globulin in preventing acute graft-versus-host disease after haploidentical haematopoietic stem cell transplantation.

To compare the clinical efficacy of porcine anti-lymphocyte globulin (p-ALG) and rabbit anti-thymocyte globulin (r-ATG) in the treatment of haematological malignancies using haploidentical haematopoietic stem cell transplantation (haplo-HSCT), this study was conducted. The incidences of neutrophil and platelet engraftment, respectively, were 100%, 93.6% and 94.4%; 100%, 93.6% and 90.3% in p-ALG 75 mg/kg (n = 57), p-ALG 90 mg/kg (n = 49), and r-ATG 7.5 mg/kg (n = 72). The median time to neutrophil engraftment and platelet engraftment were 11, 12 and 12 days (p = 0.032); 13, 14 and 13 days (p = 0.013), respectively. The incidence of grades II-IV acute graft-versus-host disease and cumulative incidence of chronic graft-versus-host disease were 16.7% versus 12.5% versus 13.3% (p = 0.817) and 14.7% versus 12.1% versus 19.5% in p-ALG 75 mg/kg, p-ALG 90 mg/kg and r-ATG groups. Notably, the cytomegalovirus infection rate in the p-ALG 75 mg/kg group was significantly lower than the other two groups. The cumulative incidence of 2-year relapse and 2-year overall survival rates were similar (p = 0.901, p = 0.497). The lower dose of p-ALG (75 mg/kg) had a similar efficacy and safety profile compared with r-ATG (7.5 mg/kg) in the setting of haplo-HSCT. Therefore, p-ALG (75 mg/kg) may be an appropriate alternative to r-ATG in the conditioning regimen of haplo-HSCT.

Evaluation of the clinical manifestations of COVID-19 in patients with aplastic anemia undergoing immunosuppressive therapy: a prospective cohort study (NICHE)

Objective: To investigate the clinical features of coronavirus disease 2019 (COVID-19) in patients with aplastic anemia (AA) undergoing immunosuppressive therapy (IST) . Methods: In this prospective cohort study, we collected the demographic and clinical data of patients with AA and COVID-19 from December 1, 2022, to January 31, 2023. We described the clinical features of COVID-19 among patients with AA and evaluated the effects of IST on the signs and severity of COVID-19. Results: A total of 170 patients with AA and COVID-19 were included. The common early symptoms, including fever, dizziness or headache, muscle or body aches, and sore throat, disappeared within 1-2 weeks. Approximately 25% of the patients had persistent fatigue within 2 weeks. Many patients experienced cough after an initial 1-3 days of infection, which lasted for more than 2 weeks. There were no differences in the duration of total fever episodes and maximum body temperature when patients were stratified according to whether or not they underwent IST, by IST duration, or by use of anti-lymphocyte globulin (ALG) (P>0.05). No differences were observed in the occurrence of symptoms in either the early or recovery stages when patients with AA were stratified according to whether or not they underwent IST, or by IST duration (P>0.05). However, patients who received ALG had fewer fever episodes within 1 week after infection (P=0.035) and more sore throat episodes within 2 weeks after infection (P=0.015). There were no other significant differences in clinical symptoms between patients who did and patients who did not receive ALG (P>0.05) . Conclusion: The majority of patients with AA and COVID-19 recovered within 2 weeks of noticing symptoms when treated with IST.

Effectiveness of In Vivo T-Cell Depleted Regimen Containing Porcine Antilymphocyte Globulin and Rabbit Antithymocyte Globulin in Preventing Acute Gvhd after Haploid Hematopoietic Stem Cell Transplantation

Objective To compare the clinical efficacy of porcine antilymphocyte globulin (p-ALG) and rabbit antithymocyte globulin (r-ATG) in the treatment of hematologic malignancies using haploid hematopoietic stem cell transplantation (haplo- HSCT), this study was conducted. Methods This was a single center retrospective analysis of 178 subjects who received haplo-HSCT with p-ALG or r-ATG from January 2020 to December 2022. The patients were divided into three groups according to the doses of p-ALG or r-ATG used in the conditioning regimens. The study evaluated and compared the occurrence of early fever, graft versus host disease (GVHD), infection, and survival among the three groups of patients. Results A total of 178 patients were enrolled in the study with a median age of 30 (14-61) years, including 95 men and 83 women. The median follow-up time post-transplantation was 20.1 (1.7-36.9) months. The study included 57 patients in the p-ALG 75mg/kg group, 49 patients in the p-ALG 90mg/kg group, and 72 patients in the r-ATG 7.5mg/kg group, respectively. The incidences of neutrophil and platelet engraftment, respectively, were 100%,93.5%, and 91.3% (p=0.133); 100%, 93.6%, 90.3% (p=0.033) in P-ALG 75mg/kg, P-ALG 90mg/kg and r-ATG 7.5mg/kg. The median time to neutrophil engraftment was 11 days for the P-ALG 75mg/kg group, 12 days for the P-ALG 90mg/kg group, and 12 days for the r-ATG 7.5mg/kg group (p=0.133). The median time to platelet engraftment was 12 days for the P-ALG 75mg/kg group, 14 days for the P-ALG 90mg/kg group, and 13 days for the r-ATG 7.5mg/kg group (p=0.033). In the p-ALG 75mg/kg, p-ALG 90mg/kg, and r-ATG 7.5mg/kg groups, 16 patients (28.1%), 24 patients (49.0%) and 35 patients (48.6%) developed fever within 14 days after transplantation, respectively. Cytokine release syndrome was found to be the most common cause of fever. The incidence of grades Ⅱ-Ⅳ acute GVHD (aGVHD) and grades Ⅲ-Ⅳ aGVHD, respectively, were 15.8%, 12.2%, and 12.5% (p=0.853); 5.3%, 2.0%, and 5.6% (p=0.523) in P-ALG 75mg/kg, P-ALG 90mg/kg and r-ATG 7.5mg/kg. The cumulative incidence of chronic GVHD at 1 year was 14.0%, 10.2%, and 15.3% (p=0.731) in the three groups. 43.9%, 71.4%, and 61.1% of patients in the p-ALG 75mg/kg, p-ALG 90mg/kg and r-ATG 7.5mg/kg groups, respectively, experienced at least one infection within 1 year after haplo-HSCT (p=0.0.13). Notably, the CMV infection rate in the p-ALG 75mg/kg group was significantly lower than in the p-ALG 90mg/kg and r-ATG 7.5mg/kg groups. The 2-year overall survival (OS) rates of p-ALG 75mg/kg, p-ALG 90mg/kg and r-ATG 7.5mg/kg groups were 78.2%, 70.6%, and 72.3% (p=0.491). The cumulative incidence of 2-year relapse were 33.0%, 29.8%, and 30.0% (p=0.834). ConclusionsCompared with r-ATG group, the p-ALG 75mg/kg group showed a lower incidence of infection. However, there were no significant differences between the two groups in terms of the incidence of grades Ⅱ-Ⅳ aGVHD, 2-year overall survival (OS), and 2-year cumulative incidence of relapse. p-ALG (75mg/kg) has a comparable effect on the prevention of GVHD after haplo-HSCT with a lower incidence of infection. Keywords: Porcine antilymphocyte globulin; Rabbit antithymocyte Globulin; Haploidentical hematopoietic cell transplantation; Graft versus host disease; Infection

The effect of on-demand glucocorticoid strategy on the occurrence and outcome of p-ALG-associated serum sickness in aplastic anemia

Objective: To investigate the effect of on-demand glucocorticoid strategy on the occurrence and outcome of porcine anti-lymphocyte globulin (p-ALG) -associated serum sickness in aplastic anemia (AA) . Methods: The data of AA patients who received in the Anemia Diagnosis and Treatment Center of Haematology Hospital, CAMS & PUMC from January 2019 to January 2022 were collected. Among them, 35 patients were enrolled in the on-demand group, with the glucocorticoid strategy adjusted based on the occurrence and severity of serum sickness; 105 patients were recruited in the usual group by matching the age and disease diagnosis according to 1∶3 ratio in patients who received a conventional glucocorticoid strategy in the same period. The incidences, clinical manifestations, treatment outcomes of serum sickness, and glucocorticoid dosage between the two groups were analyzed. Results: The incidences of serum sickness in the on-demand group and the usual group were 65.7% and 54.3% (P=0.237) , respectively. The median onset of serum sickness was the same [12 (9, 13) d vs the 12 (10, 13) d, P=0.552], and clinical symptoms and signs, primarily joint, and/or muscle pain, fever, and rash were similar. Severity grades were both dominated by Grades 1-2 (62.8% vs 51.4%) , with only a few Grade 3 (2.9% vs 2.9%) , and no Grades 4-5. No significant difference in the serum sickness distribution (P=0.530) . The median duration of serum sickness was the same [5 (3, 7) d vs 5 (3, 6) d, P=0.529], and all patients were completely cured after glucocorticoid therapy. In patients without serum sickness, the average dosage of prophylactic glucocorticoid per patient in the usual group was (469.48 ±193.57) mg (0 in the on-demand group) . When compared to the usual group, the average therapeutic glucocorticoid dosage per patient in the on-demand group was significantly lower [ (125.91±77.70) mg vs (653.90±285.56) mg, P<0.001]. Conclusions: In comparison to the usual glucocorticoid strategy, the on-demand treatment strategy could significantly reduce glucocorticoid dosage without increasing the incidence of serum sickness; in addition, the duration of serum sickness and the incidence of above Grade 2-serum sickness were similar.

Impact of Prophylactic Norfloxacin in Multidrug Resistant Bacterial Infections in the Early Liver Posttransplant Period

Norfloxacin is indicated as primary or secondary prophylaxis for spontaneous bacterial peritonitis in patients with cirrhosis. A history of spontaneous bacterial peritonitis favors colonization by multidrug-resistant bacteria. Infections caused by these bacteria increase morbidity and mortality after transplant. We investigated prophylactic norfloxacin as a risk factor for multidrug-resistant bacterial infections in the early posttransplant period. This prospective cohort study included all adult liver recipients in 2 centers between 2015 and 2016. Recipients were classified into 2 groups according to whether or not they received prophylactic norfloxacin pretransplant. Data collection from liver recipients included pretransplant and first month after transplant clinical and microbiological data. Demographic and clinical data of corresponding donors were also collected. We included 157 liver recipients: 54 (34.6%) received norfloxacin and 103 (65.6%) did not received norfloxacin. There were 63 postoperative infections in 47 recipients (29.9%); 17/63 (27%) were multidrug- resistant bacterial infections. The urinary tract was the most commonly affected site (10/17 episodes, 58.8%), and Klebsiella pneumoniae was the microorganism most often isolated (8/17, 47.1%). Incidence of multidrug-resistant bacterial infection was higher in the norfloxacin group (22.2% vs 4.9%; relative risk = 5.6, 95% CI, 1.85-16.89; P = .001).This association was significant after controlling for most confounding factors, including pretransplant vasoactive support (P = .03), Model for End-Stage Liver Disease score (P = .01), previous spontaneous bacterial peritonitis (P = .02), chronic renal impairment (P = .005), number of packed red blood cells (P = .004), use of antilymphocyte globulin as induction (P = .006), and hepatocellular carcinoma (P = .02), but not pre- transplant antibiotic treatment (P = .06). For recipients who have received prophylactic norfloxacin, clinicians should be aware of the high risk of multidrug-resistant bacterial infections during the first month after liver transplant.

LIS1, a glyco-humanized swine polyclonal anti-lymphocyte globulin, as a novel induction treatment in solid organ transplantation.

Anti-thymocyte or anti-lymphocyte globulins (ATGs/ALGs) are immunosuppressive drugs used in induction therapies to prevent acute rejection in solid organ transplantation. Because animal-derived, ATGs/ALGs contain highly immunogenic carbohydrate xenoantigens eliciting antibodies that are associated with subclinical inflammatory events, possibly impacting long-term graft survival. Their strong and long-lasting lymphodepleting activity also increases the risk for infections. We investigated here the in vitro and in vivo activity of LIS1, a glyco-humanized ALG (GH-ALG) produced in pigs knocked out for the two major xeno-antigens αGal and Neu5Gc. It differs from other ATGs/ALGs by its mechanism of action excluding antibody-dependent cell-mediated cytotoxicity and being restricted to complement-mediated cytotoxicity, phagocyte-mediated cytotoxicity, apoptosis and antigen masking, resulting in profound inhibition of T-cell alloreactivity in mixed leucocyte reactions. Preclinical evaluation in non-human primates showed that GH-ALG dramatically reduced CD4+ (p=0.0005,***), CD8+ effector T cells (p=0.0002,***) or myeloid cells (p=0.0007,***) but not T-reg (p=0.65, ns) or B cells (p=0.65, ns). Compared with rabbit ATG, GH-ALG induced transient depletion (less than one week) of target T cells in the peripheral blood (<100 lymphocytes/L) but was equivalent in preventing allograft rejection in a skin allograft model. The novel therapeutic modality of GH-ALG might present advantages in induction treatment during organ transplantation by shortening the T-cell depletion period while maintaining adequate immunosuppression and reducing immunogenicity.

A complex puzzle realized: US achieves one-millionth organ transplant: Decades of visionary scientists, skilled surgeons, and courageous patients have made this miraculous milestone a reality

A complex puzzle realized: US achieves one-millionth organ transplant: Decades of visionary scientists, skilled surgeons, and courageous patients have made this miraculous milestone a reality

Profile and Predictors of Infection Following Anti-thymocyte Globulin or Anti-lymphocyte Globulin with Cyclosporine in Aplastic Anemia.

Immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG) and Cyclosporine (CSA) in aplastic anaemia (AA) results in improvement of blood counts between 3 and 6months for the majority of patients. Infection is the most lethal complication in aplastic anemia and may arise due to several factors. We performed this study to determine the prevalence and predictors of specific infection types before and after IST. Six hundred and seventy-seven (546 adults; 434 males) transplant ineligible patients received ATG and CSA between 1995 and 2017. All patients who were transplant ineligible and received IST in this period were included. Infections before IST was seen in 209 (30.9%) and in 430 (63.5%) patients post IST. There were 700 infective episodes in the six months post-IST, including 216 bacterial, 78 fungal, 33 viral, and 373 culture-negative febrile episodes. Infections were highest (98, 77.8%) in very severe aplastic anaemia as compared to Severe AA (SAA) and Non-Severe AA (NSAA) (p < 0.001). Infections were also significantly higher in those who did not respond to ATG (71.1% vs. 56.8%, p = 0.003). At six months post-IST were 545 (80.5%) alive, and there were 54 (7.9%) deaths due to infection. Significant predictors of mortality were paediatric AA, very severe aplastic anaemia, pre or post ATG infections, and lack of response to ATG. Mortality was highest in those with combined bacterial and fungal infections post IST (p < 0.001). We conclude that infections are a common complication (63.5%) of IST. Mortality was highest when both bacterial and fungal infections were present. Routine use of growth factors and prophylactic antifungal and antibacterial agents was not part of our protocol, despite which 80.5% of the cohort was alive at the end of six months.

Comparison of Hematopoietic Stem Cell Transplantation and Immunosuppressive Therapy for Patients with Severe Hepatitis-Associated Aplastic Anemia

Background：Hepatitis-associated aplastic anemia (HAAA) is known as a rare variant of acquired aplastic anemia, characterized by a syndrome of bone marrow failure following the development of hepatitis. Immunosuppressive therapy (IST) or hematopoietic stem cell transplantation (HSCT) could provide lifesaving opportunities for severe HAAA patients. However, to date, no cohort has characterized treatment outcome and long-term survival between those patients receiving IST and HSCT. In this study, we aim to retrospectively evaluate the outcome of these two therapies for severe HAAA in China. Methods: Patients consecutively diagnosed as severe HAAA between August 2008 and Jan 2021 were enrolled in this study. The definition of severe HAAA is that severe aplastic anemia developed within three months after documented hepatitis. The enrollments were patients who received HSCT or IST as a first-line treatment. Patients with HSCT were conditioned as described previously with cyclophosphamide (Cy, 120-150 mg/kg, divided doses on days -6 to -2), and rabbit ATG (Thymoglobulin®, Genzyme, Cambridge, MA) (2.5mg/kg once i.v. daily on days -6 to -2) or p-ALG (Anti-lymphocyte Immunoglobulin®, Wuhan Institute of Biological Products Co., Ltd., China) (20mg/kg once i.v. daily on days -6 to -2), Fludarabine 150 mg/m2 i.v.in divided doses on days -6 to -2, with or without Busulfan (Bu, 0.8 mg/kg four times i.v. daily on days -7 and -6). IST consisted of both rabbit ATG (rATG) (3~3.75mg/kg once i.v. daily on 5 days), porcine antilymphocyte globulin (pALG)(20mg/kg once i.v. daily on 5 days), combined with a six-month course of cyclosporine (3mg per kilogram per day orally, with adjustment of the dose to maintain a blood level between 200 and 400 ng per milliliter). Probabilities of overall survival (OS), failure-free survival (FFS), and treatment-related-mortality (TRM) were calculated by Kaplan-Meier method. Results and Discussion: This study retrospectively included 94 consecutive HAAA patients, including 68 patients underwent HSCT and 26 patients receiving IST. The IST and HSCT groups were similar with respect to age and gender ratio. The median follow up were 1752 (±153.62, 95%CI 1450.90~2053.10) days, and 2648 (±321.41, 95%CI 2018.05-3277.96) days among alive patients in the IST and HSCT group, respectively. In HSCT group, all patients achieved neutrophil engraftment. No primary or secondary graft failures (GF) was documented. Compared with patients receiving alternative donor HSCT (n=11), patients in matched sibling donor HSCT (MSD-HSCT) group (n=15) had a significant lower cumulative incidence of acute graft versus host disease (aGVHD) (20±10.33% vs 56.4±15.47%, p=0.048), and lower incidence of cytomegalovirus (CMV) reactivation group (72.73% vs 13.33%, p=0.004). No clinical significance of chronic graft versus host disease (cGVHD) incidence group (43.4±18.85% vs 50±35.4%, p=0.78) and bacterial/fungus infection (26.67% vs 36.36%, p=0.683) was found between MSD-HSCT group and alternative donor-HSCT. Attributable causes of death were pneumonias and severe infection in patients receiving HSCT. In IST group, the hematology response rate to treatment evaluated at 3m, 6m and 12m was 27.68%, 52.94%, and 60.23%, respectively. There were thirteen patients were non-evaluable, including six patients transferred to perform HSCT, two patients were diagnosed MDS/AML transformation and one patient relapsed. The 5-year overall survival (OS) and failure-free survival (FFS) rate was 85.5±4.44% (95% CI, 0.772, 0.946) and 69.6± 5.35% (95% CI, 0.599,0.809) of all enrolled HAAA patients, respectively (Figure 1). For patients receiving different therapy, the 5-year OS rates were 92.86 ± 6.88% in MSD-HSCT group, 72.7± 13.43% in alternative donor-HSCT, and 84.1 ± 7.28% in the IST group (P = 0.56). Otherwise, the 5-year estimated FFS rate was 56.0± 11.51% in the IST group, compared with 92.86 ± 6.88% in the MSD-HSCT group and 72.7± 13.43% in alternative donor-HSCT group (P = 0.10). The cumulative incidence of treatment-related-mortality (TRM) of MSD-HSCT, alternative-HSCT and IST was 7.1±6.9% (95% CI, 80.30-100), 27.3±13.4% (95% CI, 50.60-100), 14±5.54% % (95% CI, 7.58-97.6) (p=0.22), respectively. Even there was no difference between the HSCT and IST groups in OS, MSD-HSCT group still showed superior FFS. Patients receiving alternative donor HSCT, and IST showed comparable OS and FFS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Long-Term Outcome of Low Dose of Anti-t-Lymphocyte Globulin in the Prophylaxis of Graft-Versus-Host Disease in Unrelated Myeloablative Hematopoietic Stem Cell Transplantation

INTRODUCTION In vivo T-cell depletion with Anti-T-lymphocyte globulin (ATLG; Grafalon) is one of the strategies used in the graft-versus-host disease (GVHD) prevention in the setting of hematopoietic stem cell transplantation (HSCT). One open-label randomized trial in HLA-matched unrelated myeloablative HSCT have reported the reduction of cGVHD with the incorporation of ATLG (60mg/Kg), however progression-free survival (PFS) and overall survival (OS) were lower than in the placebo group1. Other randomized trial in related myeloablative HSCT, using an inferior dose of ATLG (30mg/Kg), have reported this reduction in GVHD results without increasing transplantation-related mortality (TRM) or disease relapse (DR)2. Based on this, the policy in our center is to use a lower dose of ATLG (21mg/Kg) in unrelated myeloablative HSCT. The aim of this study is to analyze the outcome of this strategy in terms of GVHD results, PFS, OS, TRM and DR. METHODS We conducted a retrospective study in all patients who underwent a HLA-matched unrelated myeloablative HSCT at our institution between 2013 and 2021. Patients received a total dose of 21mg/Kg of ATLG divided into three doses of 7mg/Kg on days -3, -2 and -1. The primary endpoints were cumulative incidence (CI) of aGVHD, CI of moderate-severe cGVHD, PFS and OS. Secondary endpoints were TRM, CI of DR and toxicity. RESULTS Sixty-one patients were included. The median age was 51 years. Thirty-seven (60,7%) were men. Twenty-three (37,7%) patients had an acute myeloid leukemia (AML). Eighteen (29,5%) patients had an HLA-mismatched donor. Forty-two (68,8%) receive a Bu-Flu conditioning. Cyclosporine combined with mycophenolate mofetil (MMF) or short course of methotrexate (MTX) as GCVH prophylaxis was used in 43 patients (70,5%). Clinical characteristics of patients are showed in table 1. The median follow-up of the alive patients was 36 months. A median value of 0.1 x 106/L lymphocytes was observed on the first day of infusion. In 35 patients (57,4%) a grade 1 to 2 infusion reaction was reported and in 3 (4,9%) a grade 3 to 4. Those three patients did not complete all infusions, the rest of patients did. Median time to neutrophil engraftment (3 consecutive days of >500/μL) was 15 days (IR, 13-18) and to platelet engraftment (3 consecutive days of self-supported platelets >20000/μL) was 17 days (IR, 15-23). CI of aGVHD grade 2 to 4 within 180 days after HSCT was 39,5% (95% CI, 27,1% to 51,6%) and CI of aGVHD grade 3 to 4 was 11,6% (95% CI, 5,0% to 21%), CI of moderate-severe cGVHD at two years was 20,9% (95% CI, 11,4% to 32,4%). PFS at two years was 59,6% (95% CI, 47% to 71%) and OS at two years was 71,8% (95% CI, 59% to 83%). The cGVHD relapse free survival (cGRFS) at two years was 36,2% (95 CI, 24% to 48%). The CI of RD at two years was 23,3% (95% CI, 13% to 35,3%) and the TRM at two years was 17,1% (95% CI, 8,7% to 27,9%). Median time to cyclosporine or tacrolimus withdrawal was 6,7 months (interquartile range, 5-8 months) and median of use of any type of immunosuppressors (i.e corticosteroids) from the day of HSCT was 6,9 months (interquartile range, 5-10 months). In 4 (6,6%) patients a primary graft failure was reported, and two patients developed post-transplantation lymphoproliferative disease. CONCLUSSIONS The use of ATLG at dose of 21 mg/Kg in HLA-matched unrelated myeloablative HSCT offers promising results of OS and PFS with a low TRM, despite being related to a higher incidence of aGVHD and cGVHD than previously trials were the ATLG dose was higher. It showed a better profile of tolerability and adverse effects. More investigation should be undertaken to determine the appropriate dose of ATLG in this type of HSCT. REFERENCES 1. Soiffer RJ, Kim HT, McGuirk J, Horwitz ME et al. Randomized, Double-Blind, Phase III Clinical Trial of Anti-T-Lymphocyte Globulin to Assess Impact on Chronic Graft-Versus-Host Disease-Free Survival in Patients Undergoing HLA-Matched Unrelated Myeloablative Hematopoietic Cell Transplantation. J Clin Oncol. 2017 Dec 20;35(36):4003-4011. doi: 10.1200/JCO.2017.75.8177. Epub 2017 Oct 17. PMID: 29040031; PMCID: PMC8462523. 2. Kröger N, Solano C, Wolschke Cet al. Antilymphocyte Globulin for Prevention of Chronic Graft-versus-Host Disease. N Engl J Med. 2016 Jan 7;374(1):43-53. doi: 10.1056/NEJMoa1506002. PMID: 26735993. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P-027: SICKLE CELL DISEASE AND AUTOIMMUNE LIVER DISORDERS: SHOULD HEMATOPOIETIC STEM CELL TRANSPLANTATION BE DISCUSSED EARLY?

Purpose: Patients with sickle cell disease (SCD) are prone to dys- or autoimmune disorders, such as autoimmune hepatitis (AIH), sclerosing cholangitis, or ulcerative colitis. Sclerosing cholangitis can develop in young children with an unusually severe course due to associated vaso-occlusion and ischemia. Liver transplantation may be indicated early but is a challenging procedure in SCD, with uncertain outcomes (Hurtova Liver Transpl 2011, Duvoux [abstract] JFHOD 2021). Hematopoietic stem cell transplantation (HSCT) can cure SCD, although conditioning may induce hepatic complications. Herein we report a series of 6 children with SCD and autoimmune disorders, 3 for whom liver or digestive symptoms resolved after successful HSCT, and 3 for whom cirrhosis precluded HSCT conditioning. Materials and methods: Of the 6 children (5 girls), 5 were HbSS and 1 was HbSC. Dysimmune symptoms appeared at a median age of 4.5 (3-12) years and were colitis (n=2), cerebral vasculitis (n=1), and AIH (n=3). In 4/6 patients, liver disease was an overlap AIH-sclerosing cholangitis, while 2/6 patients had either isolated AIH or sclerosing cholangitis. Liver biopsy showed cirrhosis in 3 patients. Median age at last follow-up (FU) was 13.5 (8-17) years. Results: The 3 patients without cirrhosis, including 2 with sclerosing cholangitis and dilated bile ducts, underwent HSCT with a geno-identical donor, at 6, 11.5 and 16 years old. Autoimmune disease was controlled with steroids, azathioprine, infliximab or cyclophosphamide with plasma exchanges and rituximab. Conditioning included hepatotoxic drugs busulfan (n=2) and treosulfan (n=1), with antilymphocyte globulins, fludarabine (n=3) and thiotepa (n=1). Transient hepatitis developed in 1 patient and moderate graft-vs-host disease (GVHD) in 2, which resolved after adapting immunosuppression treatment. HSCT was uneventful in the third patient. With a FU of 1 to 2.5 years, all 3 patients had no digestive or liver symptoms, normal or mildly elevated liver enzymes and unchanged liver imaging. The 3 patients with cirrhosis upon first visit, at ages 7, 8.5, 13 years old, were on regular exchange transfusions at last FU. One patient developed recurrent infectious cholangitis and received a liver transplant at age 10, with many complications; at 7 years of FU, sclerosing cholangitis relapsed and re-transplantation was discussed. Another had moderate portal hypertension, bilirubin levels of 100-200 µM, and prothrombin time 60%, on steroids. The third patient was on tacrolimus, had presented 2 episodes of reversible liver failure, bilirubin levels of 100 µM and prothrombin time 45% at last FU and had developed myasthenia. Conclusion: Autoimmune liver disease in children with SCD may rapidly lead to end-stage liver disease. Upon diagnosis, these disorders should be considered as severe complications of SCD and prompt early discussion of HSCT. HSCT should be performed before conditioning with hepatotoxic drugs is not feasible. If a geno-identical donor is not available, alternative donors could be considered (haplo-identical, unrelated). If the liver disease is not stabilized after HSCT, liver transplantation could be performed with a standard risk, in a patient rid of SCD. If liver transplantation must be performed before HSCT, HSCT could be discussed rapidly afterwards to avoid possible relapse of SCD-related liver disease and dysimmune liver disease. The authors do not declare any conflict of interest

Impact of Anti-T-lymphocyte globulin dosing on GVHD and Immune reconstitution in matched unrelated myeloablative peripheral blood stem cell transplantation

Data on the influence of different Anti-lymphocyte globulin (ATLG) doses on graft versus host disease (GVHD) incidence and immune reconstitution in matched unrelated (MUD) allogeneic Stem cell transplantation (allo-SCT) is limited. This retrospective study conducted at the University Medical-Center Hamburg compares GVHD and Immune reconstitution after myeloablative MUD (HLA 10/10) PBSC allogeneic stem cell transplant between 30 mg/Kg (n = 73) and 60 mg/Kg (n = 216) ATLG. Detailed phenotypes of T, B natural killer (NK), natural killer T (NKT) cells were analyzed by multicolor flow at day 30, 100, and 180 posttransplant. Neutrophil and platelet engraftments were significantly delayed in the 60 mg/kg group with a higher Cumulative incidence of Infections (67% vs 75% p = 0.049) and EBV (21% vs 41% p = 0.049) reactivation at day 100 in this group. In the 30 mg/kg group, we observed a faster reconstitution of naïve-B cells (p < 0.0001) and γδ T cells (p = 0.045) at day+30 and a faster naïve helper T-cell (p = 0.046), NK-cells (p = 0.035), and naïve B-cell reconstitution (p = 0.009) at day+180. There were no significant differences in aGVHD, cGVHD, NRM, RI, PFS, and OS between the groups. The choice of ATLG dose has significant impact on IR but not on GVHD after MUD-allo-SCT. Higher doses are associated with delayed engraftment and increased infections.

Retrospective Comparison of Efficacy and Safety of Rabbit Anti-Thymocyte Globulin and Porcine Anti-Lymphocyte Globulin in Patients With Acquired Aplastic Anemia Undergoing Hematopoietic Stem Cell Transplantation From Matched Sibling Donors.

We compared the efficacy and safety of porcine anti-lymphocyte globulin (pALG) (n=140) and rabbit anti-thymocyte globulin (rATG) (n=86) in patients with acquired aplastic anemia (AA) receiving hematopoietic stem cell transplantation (HSCT) from matched sibling donors (MSD) in two transplantation centers in China ranging from 2005 to 2020. The groups had similar baseline characteristics except for a higher number of infused mononuclear cells (P<0.001) and a higher proportion of peripheral blood stem cells as graft sources (P=0.003) in the pALG group. The rates of neutrophil engraftment at day 28 (P=1), platelet engraftment at day 28 (P=0.228), bloodstream infection before engraftment (P=0.867), invasive fungal diseases (P=0.362), cytomegalovirus viremia (P=0.667), and graft rejection (P=0.147) were similar in the two groups. A higher cumulative incidence of grades II-IV acute graft versus host disease (aGvHD) at 100 days occurred in the pALG group (19% vs. 8%, P=0.035) while no significant differences in grades III-IV aGvHD (P=0.572), mild to severe chronic GvHD (cGvHD) (P=0.181), and moderate to severe cGvHD (P=0.586) were observed. The actuarial 5-year overall survival (OS), failure-free survival (FFS), and GvHD-free, FFS rates of the pALG group were 87% (95% confidence interval [CI], 82-93), 85% (95% CI, 80-92), and 78% (95% CI, 72-92) versus 91% (95% CI, 86-99) (P=0.33), 88% (95% CI, 82-97) (P=0.428), and 79% (95% CI, 72-90) (P=0.824) in the rATG group, respectively. A busulfan-containing conditioning regimen was the only adverse risk factor for OS and FFS in multivariate analysis. In conclusion, pALG is an alternative to rATG in patients with severe AA receiving MSD-HSCT. A prospective, large-sample study is needed to explore this therapy further.

Combining CD34+ stem cell selection with prophylactic pathogen and leukemia directed T-cell immunotherapy to simultaneously reduce graft versus host disease, infection, and leukemia recurrence after allogeneic stem cell transplant.

We designed a trial to simultaneously address the problems of graft versus host disease (GVHD), infection, and recurrence of malignancy after allogeneic stem cell transplantation. CD34+ stem cell isolation was used to minimize the development of acute and chronic GVHD. Two prophylactic infusions, one combining donor-derived cytomegalovirus, Epstein-Barr virus, and Aspergillus fumigatus specific T-cells and the other comprising donor-derived CD19 directed chimeric antigen receptor (CAR) bearing T-cells, were given 21-28 days after transplant. Two patients were transplanted for acute lymphoblastic leukemia from HLA identical siblings using standard doses of cyclophosphamide and total body irradiation without antilymphocyte globulin. Patients received no post-transplant immune suppression and were given no pre-CAR T-cell lymphodepletion. Neutrophil and platelet engraftment was prompt. Following adoptive T-cell infusions, there was rapid appearance of antigen-experienced CD8+ and to a lesser extent CD4+ T-cells. Tetramer-positive T-cells targeting CMV and EBV appeared rapidly after T-cell infusion and persisted for at least 1 year. CAR T-cell expansion occurred and persisted for up to 3months. T-cell receptor tracking confirmed the presence of product-derived T-cell clones in blood targeting all three pathogens. Both patients are alive over 3 years post-transplant without evidence of GVHD or disease recurrence. Combining robust donor T-cell depletion with directed T-cell adoptive immunotherapy targeting infectious and malignant antigens permits independent modulation of GVHD, infection, and disease recurrence. The combination may separate GVHD from the graft versus tumor effect, accelerate immune reconstitution, and improve transplant tolerability.

Comparison of porcine ALG and rabbit ATG on outcomes of HLA-haploidentical hematopoietic stem cell transplantation for patients with acquired aplastic anemia

ObjectiveTo evaluate the efficacy and safety of P-ALG (porcine anti-lymphocyte globulin) and R-ATG (rabbit anti-thymocyte globulin) in the conditioning regime for patients with acquired aplastic anemia who underwent HLA-haploidentical hematopoietic stem cell transplantation (halpo-HSCT).MethodsA total of 91 patients with acquired aplastic anemia who received haplo-HSCT at our center between January 2014 and December 2020 were retrospectively reviewed. Twenty-eight patients were in the P-ALG group while sixty-three patients were in the R-ATG group.ResultsThe median time was 11 versus 13 days (P = 0.294) for myeloid engraftment and 12.5 versus 15 days (P = 0.465) for platelet engraftment in the P-ALG and R-ATG groups, respectively. There were no significant difference in 5-year overall survival (74.83% ± 8.24% vs 72.29% ± 6.26%, P = 0.830), GVHD-free, failure-free survival (71.05% ± 8.65% vs 62.71% ± 6.22%, P = 0.662), failure-free survival (74.83% ± 8.24% vs 66.09% ± 5.84%, P = 0.647) and transplantation-related mortality (25.17% ± 8.24% vs 26.29% ± 6.22%, P = 0.708) between the two groups. The incidence of aGVHD (acute graft versus host disease) (65.39% ± 9.33% vs 62.71% ± 6.30%, P = 0.653), II–IV aGVHD (38.46% ± 9.54% vs 35.64% ± 6.24%, P = 0.695), III–IV aGVHD (19.23% ± 7.73% vs 10.53% ± 4.07%, P = 0.291), cGVHD (chronic graft versus host disease) (22.22% ± 12.25% vs 22.31% ± 6.30%, P = 0.915), and moderate to severe cGVHD (5.56% ± 5.40% vs 9.28% ± 4.46%, P = 0.993) were not significantly different. Similar outcomes were observed between the P-ALG and R-ATG groups for severe bacterial infection (17.9% vs 25.4%, P = 0.431), invasive fungal diseases (3.6% vs 9.5%, P = 0.577) and graft rejection (0% vs 9.5%, P = 0.218). However, the incidence of cytomegalovirus infection and Epstein-Barr virus infection was significantly lower in the P-ALG group (46.4% vs 71.4%, P = 0.022; 3.6% vs 25.4%, P = 0.014).ConclusionThe efficacy and safety of P-ALG were similar with R-ATG in the setting of haplo-HSCT for patients with acquired aplastic anemia patients. P-ALG could be an alternative for R-ATG.

Aberrant Dntt Expression, TdT-Aided Gene Length Mutations, and Prognosis Relevance in ATG/Alg Based Regimen Allo-HSCT in Acute Myeloid Leukemias

DNTT encodes the most template-independent DNA polymerases TdT. The canonical function of TdT is to boost the diversity of immunoglobulin and T cell receptors by incorporating non-templated nucleotides (NTN) to their variable regions via RAG1/2 mediated DNA breaks and non-homologous end joining (NHEJ) rearrangement process. This study aimed to investigate the relationship between aberrant DNTT expression and illegitimately TdT-aided microhomology-mediated replication-dependent recombination (MMRDR) with the mutagenesis of gene length mutations (LMs) in acute myeloid leukemia (AML), and their prognosis relevance.A cohort of 578 AML cases was enrolled. Fifty healthy donors for allogeneic hematopoietic stem cell transplantation (allo-HSCT), 393 B cell acute lymphoblastic leukemia (B-ALL) cases, 78 T-ALL cases, and 25 mixed-phenotype acute leukemia (MPAL) cases were used as control. Next-generation sequencing was performed for mutation analysis of 86 leukemia driver genes. RNA-seq was used to analyze the expression of DNTT and other non-homologous end joining (NHEJ) associated genes. Prognostic was investigated in a subset of 239 AML cases who underwent anti-thymocyte globulin (ATG) or anti-lymphocyte globulin (ALG) based regimen allo-HSCT.Based on sequence anatomy that considers the MMRDR mechanism and nucleotides characteristics of TdT mediated NTN incorporation, we formulate a classification algorithm for LMs and divide them into four subtypes (type I-IV). Type-I indicates pure duplicated/triplicated germline sequences with identifiable ≥2bp canonical triple microhomology (MH) sequences; type-II indicates pure duplicated/triplicated germline sequences without ≥2bp canonical MH sequences; type-III indicates any LMs with NTN insertions; type-IV indicates any other LMs, mainly deletions.FLT3-LMs has the highest overall incidence and occur across multiple lineage leukemias. We observed a significant FLT3-LMs subtypes distribution bias among acute leukemia subtypes (Figure 1A). Type-I FLT3 LMs are only observed in AML; there are mainly type-III FLT3 LMs in T-ALL and MPAL; type-II, III, IV FLT3 LMs are predominant in B-ALL. The overall DNTT expression was significantly lower in AML than in other leukemia subtypes and control groups (P < 0.001). This supports that FLT3-LMs subtypes distribution bias might be attributed to the difference in the overall DNTT expression among leukemia lineages.A total of 458 LMs events were observed in 295 cases (51.0%) within 25 genes (FLT3, NPM1, CEBPA, RUNX1, KIT, etc.) in our AML cohort. The incidence of type-II and type-III LMs, both of which the mutagenesis relies on TdT-aided MMRDR in theoretically speculate, were 31.2 % and 47.8 %, respectively. Type-I and type-II, which manifested as pure germline sequence duplications, account for 43.6% of the FLT3 LMs; type-III LMs, which with additional inserted NTN sequences, account for as high as 50.4% of the FLT3 LMs.We analyzed the G/C nucleotide contents adjacent to LMs junctions. A significantly high G/C bias was observed at +1 nucleotide position in type-II and type-III subsets (Figure 1B), suggesting that the TdT-aided MMRDR mechanism plays a role in the mutagenesis in these cases. We also observed a strong positive correlation between fragment length and G/C content of the inserted NTN sequences (P < 0.001) within the type-III subset of the 25 LMs genes (Figure 1C), suggesting a higher TdT activity mediates longer inserted sequences.DNTT expressions level of type-III LMs cases were significantly higher than that of type-I, II, IV LMs cases and cases without LMs in the total 25 LMs genes (Figure 1D) and the FLT3 LMs subset. Similar expression signatures of other NHEJ associated genes RAG2, XRCC4, and XRCC6 were also observed. For the survival analysis in the ATG/ALG based regimen allo-HSCT AML subset, we observed a significantly better overall survival (P = 0.024) in cases positive for type-III FLT3-LMs than that of type-I, II (Figure 1E).In this study, we proposed a subclassification algorithm for LMs (type I-IV) in AML. Both DNTT gene expression and sequence character suggesting that TdT-aided MMRDR plays a role in the mutagenesis of type-III and type-II LMs. We also observed AML cases with type-III FLT3 LMs benefit more from ATG/ALG based regimen allo-HSCT than cases with other FLT3 LMs types, which may be attributed to the aberrant lymphoid lineage antigen expression. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.