Comparison of efficacy of eltrombopag combined with immunosuppression in the treatment of severe aplastic anemia and very severe aplastic anemia: real-world data and evidence.

Eltrombopag combined with immunosuppressive therapy (IST) was superior to IST alone for severe aplastic anemia (SAA) in the previous studies. But in China, horse antithymocyte globulin (hATG) is not available, instead, we use rabbit ATG (rATG). Here, we compared the efficacy and safety of IST (rATG combined with cyclosporine) combined with or without eltrombopag for the first-line treatment of SAA and very severe aplastic anemia (VSAA). A total of 371 patients in ten institutions in China from April 1, 2017 to December 1, 2022 were enrolled. The overall response (OR) rate at 3 months (54.2% vs. 41%; P = 0.046), the complete response (CR) (31.3% vs. 19.4%; P = 0.041) and OR (78.3% vs. 51.1%; P < 0.0001) rates at 6 months were significantly higher with IST combined with eltrombopag than with IST alone in SAA patients. While in VSAA patients, the addition of eltrombopag to IST only increased the CR rate at 6 months (29.8% vs. 9.43%; P = 0.010). Liver injury increased significantly in groups treated with IST combined with eltrombopag (P < 0.05). Serious treatment-related toxicities were similar (P > 0.05). In patients with SAA, 3-year failure-free survival (FFS) of eltrombopag combined with IST group was significantly higher than that of IST group (70.7 ± 5.3% vs. 50.3 ± 3.9%; P = 0.007). In patients with VSAA, the addition of eltrombopag significantly improved 3-year overall survival (OS) (82.2 ± 5.7% vs. 57.3 ± 7.2%; P = 0.020). Our findings suggested that IST combined with eltrombopag could improve the hematological recovery of newly diagnosed SAA without increasing severe toxicities. But in VSAA, the addition of eltrombopag seemed to show no other improvement to efficacy except the CR rate at 6 months.

Unrelated umbilical cord blood transplantation with low-dose anti-thymocyte globulin for children with severe aplastic anemia: A case series.

OBJECTIVE: This study aimed to investigate the prognosis of unrelated umbilical cord blood transplantation (UCBT) using low-dose anti-thymocyte globulin (ATG) in children diagnosed with severe aplastic anemia (SAA). METHODS: This retrospective case series study was conducted involving pediatric SAA patients treated at the Capital Institute of Pediatrics from January 2020 to February 2023. All patients underwent a reduced-intensity conditioning (RIC) regimen alongside low-dose ATG. RESULTS: The study comprised nine patients (five males) with a median age of 5 years (range: 1.7 to 7 years). The median follow-up duration was 799 days (range: 367 to 1481 days), during which all patients survived. The median time interval from diagnosis to transplantation was 3 months (range: 1 to 9 months). The median dosage of ATG administered was 5 mg/kg (range: 2.5 to 7.5 mg/kg). The median durations for granulocyte and platelet engraftment were 15 days (range: 12 to 23 days) and 26 days (range: 12 to 41 days), respectively. Three patients experienced grade 2-4 acute graft-versus-host disease (aGVHD). Epstein-Barr virus (EBV) reactivation was observed in three patients, while cytomegalovirus (CMV) reactivation occurred in seven patients, with no cases of CMV disease or post-transplant lymphoproliferative disorder (PTLD). One patient experienced recurrence 15 months after transplantation due to influenza A infection. CONCLUSION: These findings indicate that SAA patients may attain a favorable prognosis following UCBT with a RIC regimen combined with low-dose ATG.

Long-Term Follow-Up of Eltrombopag Treatment for Patients with Cyclosporin A Refractory/Relapsed Transfusion-Dependent Non-Severe Aplastic Anemia: A Report from a Single Center in China.

INTRODUCTION: Aplastic anemia (AA) is characterized by bone marrow failure and cytopenia. Eltrombopag (ELT) is effective and safe for treating refractory/relapsed AA; however, reports on the long-term outcomes of transfusion-dependent non-severe AA (TD-NSAA) are limited. METHODS: Patients with TD-NSAA refractory to immunosuppressive therapy (IST) or relapsed after IST, treated with ELT alone, and followed up for at least 12 months were retrospectively enrolled. The baseline characteristics of patients, efficacy and adverse effects of ELT, and relapse and clone evolution rates after ELT were documented. RESULTS: Of the 55 patients with TD-NSAA included, 24 (43.6%) were men. Median age at diagnosis was 46 (19-80) years. Twenty-four patients had relapsed TD-NSAA, and 31 patients had refractory TD-NSAA. During the median follow-up period of 28 (12-48) months, the overall and complete response rates at 3, 6, and 12 months of ELT treatment were 38.2, 60.0, and 52.7 and 9.1, 14.6, and 9.1%, respectively. After a median follow-up of 28 (12-48) months, 21.2% (7/33) of patients experienced relapse, with a median duration from ELT treatment to relapse of 14 (6-45) months. CONCLUSION: ELT was effective in patients with relapsed/refractory TD-NSAA, with tolerable adverse effects.

The role of donor type and pre-transplant immunosuppression on outcomes of hematopoietic stem cell transplantation in children and young adults with severe aplastic anemia.

BACKGROUND: The goal of this study was to assess the effect of donor type and pre-transplant immunotherapy (IST) on outcomes of hematopoietic stem cell transplantation (HSCT) for children and young adults with severe aplastic anemia (SAA). METHODS: This retrospective, multi-center study included 52 SAA patients, treated in 5 pediatric transplant programs in Florida, who received HSCT between 2010 and 2020 as the first- or second-line treatment. RESULTS: The median age at HSCT for all 52 patients was 15 years (range 1-25). The 3-year overall survival (OS) by donor type were as follows: 95% [95% CI 85.4-99] for matched related donors (MRD) (N = 24), 84% [95% CI 63.5-99] for haploidentical (N = 13), and 71% [95% CI 36-99] for matched unrelated donors (MUD) (N = 7). The 3-year OS was 81% [95% CI 69.7-99] for all patients, 90.5% [95% CI 79.5-99] for non-IST patients (N = 27), and 70% [95% CI 51-99] for IST patients (N = 24) (log-rank p = .04). Survival of haploidentical HSCT (haplo-HSCT) recipients with post-transplant cyclophosphamide (PTCy) (N = 13) was excellent for both groups: 100% for non-IST patients (N = 3) and 80% for IST patients (N = 10). The 3-year OS for patients with previous IST by donor type in groups where >5 patients were available was 78.8% [95% CI 52.3-99] for haplo-HSCT (N = 10) and 66.7% [95% CI 28.7-99] for MUD (N = 6). Although it appears that patients receiving HSCT ≥6 months after the start of IST had worse survival, the number of patients in each category was small and log-rank was not significant(p = .65). CONCLUSIONS: Patients receiving MUD and haplo-HSCT with PTCy had similar outcomes, suggesting that haplo-HSCT with PTCy could be included in randomized trials of upfront IST versus alternative donor HSCT.

Molecular mechanisms underlying the role of HLA-DQ in systemic immune activation in severe aplastic anemia.

Severe aplastic anemia (SAA) is a bone marrow failure disorder caused by autoimmune dysfunction. The presentation by dendritic cells (DCs) is the key step in initiating the immune response against unknown antigens in SAA patients. In the previous phase, we found that compared to healthy controls, patients with SAA had an increased proportion of circulating myeloid/conventional dendritic cells (mDCs/cDCs) with enhanced phagocytosis, more secretion of Th1-type cytokines (IL-2, TNF-α, IFN-γ) in the bone marrow, and a reduced proportion of Treg cells. In this study, we found that cDCs sorted from SAA patients had higher expression level of HLA-DQ, co-stimulatory molecules CD86, PTK and ERK1/2 than the remission SAA patients and healthy controls. Moreover, downregulation of HLA-DQ protein levels on cDCs derived from SAA patients resulted in reduced phagocytosis rate and CD86 expression of cDCs. When the cDCs above were co-cultured with CD4+ cells from the same patients, reduced secretion of Th1 type of lymphocyte cytokines was observed. Analysis of clinically relevant data suggests that HLA-DQ expression levels were closely related to disease severity and immune status of patients. These findings show that the role of HLA-DQ in the immunopathogenesis of SAA is potentially important and worth further study.

Single-cell analysis highlights a population of Th17-polarized CD4+ naïve T cells showing IL6/JAK3/STAT3 activation in pediatric severe aplastic anemia.

Acquired aplastic anemia (AA) is recognized as an immune-mediated disorder resulting from active destruction of hematopoietic cells in bone marrow (BM) by effector T lymphocytes. Bulk genomic landscape analysis and transcriptomic profiling have contributed to a better understanding of the recurrent cytogenetic abnormalities and immunologic cues associated with the onset of hematopoietic destruction. However, the functional mechanistic determinants underlying the complexity of heterogeneous T lymphocyte populations as well as their correlation with clinical outcomes remain to be elucidated. To uncover dysfunctional mechanisms acting within the heterogeneous marrow-infiltrating immune environment and examine their pathogenic interplay with the hematopoietic stem/progenitor pool, we exploited single-cell mass cytometry for BM mononuclear cells of severe AA (SAA) patients pre- and post-immunosuppressive therapy, in contrast to those of healthy donors. Alignment of BM cellular composition with hematopoietic developmental trajectories revealed potential functional roles for non-canonically activated CD4+ naïve T cells in newly-diagnosed pediatric cases of SAA. Furthermore, single-cell transcriptomic profiling highlighted a population of Th17-polarized CD4+CAMK4+ naïve T cells showing activation of the IL-6/JAK3/STAT3 pathway, while gene signature dissection indicated a predisposition to proinflammatory pathogenesis. Retrospective validation from our SAA cohort of 231 patients revealed high plasma levels of IL-6 as an independent risk factor of delayed hematopoietic response to antithymocyte globulin-based immunosuppressive therapy. Thus, IL-6 warrants further investigation as a putative therapeutic target in SAA.

Incidence and risk factors for secondary graft failure in uniformly treated patients with severe aplastic anemia receiving fludarabine and cyclophosphamide for conditioning and matched sibling bone marrow graft as stem cell source.

BACKGROUND AIMS: Graft failure after allogeneic transplant for aplastic anemia is problematic. The risk of graft failure depends on multiple variables, including the preparative regimen, donor type, stem cell dose and source among other variables. METHODS: We performed a retrospective analysis of patients with aplastic anemia who underwent matched-sibling allogeneic transplant at a single center. RESULTS: We identified 82 patients who fit the inclusion criteria. One had primary graft failure and was excluded from this analysis. The recipient median age was 22 years. The donor median age was 23 years. The median time from diagnosis to transplant was 1.6 months. The median number of red cell transfusions before transplant was nine. The median number of platelet transfusions before transplant was 18. Thirteen patients developed secondary graft failure, with a cumulative incidence at 5 years of 16% and median time to develop secondary graft failure of 129 days. All patients engrafted with a median time for neutrophil engraftment of 19 days and a median time for platelet engraftment of 22 days. The survival of patients with or without secondary graft failure was not different. Major or bidirectional ABO incompatibility and older recipient age were statistically significantly associated with greater risk of secondary graft failure. CONCLUSIONS: Secondary graft failure is a significant complication after allogeneic transplant for SAA. Identification of recipients at risk and mitigating the potential risks of this complication is warranted.

Transplant for non-malignant disorders: an International Society for Cell & Gene Therapy Stem Cell Engineering Committee report on the role of alternative donors, stem cell sources and graft engineering.

Hematopoietic stem cell transplantation (HSCT) is curative for many non-malignant disorders. As HSCT and supportive care technologies improve, this life-saving treatment may be offered to more and more patients. With the development of new preparative regimens, expanded alternative donor availability, and graft manipulation techniques, there are many options when choosing the best regimen for patients. Herein the authors review transplant considerations, transplant goals, conditioning regimens, donor choice, and graft manipulation strategies for patients with non-malignant disorders undergoing HSCT.

Alternative treatment modality for severe aplastic anemia in a resource-limited setting: a single-institution prospective cohort study from Upper Egypt.

This study compared the efficacy and safety of CsA monotherapy with eltrombopag (E-PAG) + CsA combined treatment in children with severe aplastic anemia (SAA). The study including 30 children had SAA. Ten were a retrospective cohort treated with CsA monotherapy. The other 20 were prospective cohort received E-PAG + CsA. All patients were evaluated for partial (PR) and complete (CR) hematological response at 3, 6, and 12 months. overall response (OR), overall survival rates (OS), and treatment safety. OR for the E-PAG patients was 40% after 3 months of therapy. At 6 months, this had increased to 75% with significantly higher CR rate (40%) than in the CsA group (p = 0.0001). After a year of treatment, the CR for the E-PAG + CsA regimen had increased to 50% and the OR to 85%, compared to 20% in the CsA group (p = 0.0001). The OS at 12 months was 100% in the E-PAG+ CsA group compared to 80% in the CsA cohort. At 24 months, the OS in the E-PAG + CsA group was 90%. In conclusion, E-PAG+ CsA was found to be a safe and effective alternative treatment for children with SAA particularly in countries with limited resources.

Comparison of haploidentical-allogeneic hematopoietic stem cell transplantation and intensive immunosuppressive therapy for patients with severe aplastic anemia with an absolute neutrophil count of zero: a retrospective study.

A retrospective analysis was conducted based on the clinical data from 60 patients older than 16 years from January 2016 to January 2021. All the patients were newly diagnosed with severe aplastic anemia (SAA) with an absolute neutrophil count (ANC) of zero. We compared the hematological response and survival of haploidentical-allogeneic hematopoietic stem cell transplantation (HID-HSCT) (n = 25) and intensive immunosuppressive therapy (IST) (n = 35) treatments. At six months, the overall response rate and complete response were significantly higher in the HID-HSCT group than those in the IST group (84.0% vs. 40.0%, P = 0.001; 80.0% vs. 17.1%, P = 0.001). With a median follow-up of 18.5 months (4.3~30.8 months), patients in the HID-HSCT group had longer overall survival and event-free survival (80.0% vs. 47.9%, P = 0.0419; 79.2% vs. 33.5%, P = 0.0048). These data suggested that HID-HSCT might be an effective alternative treatment option for adult patients with SAA with an ANC of zero, which requires further validation in an additional prospective study.

Shifting Paradigms: The Case of Autologous Reconstitution after an Upfront Matched Unrelated Hematopoietic Cell Transplantation for Severe Acquired Aplastic Anemia in a Child.

During the last few years, the therapeutic landscape of idiopathic aplastic anemia (IAA) has been profoundly revolutionized by the increased use of alternative transplant procedures, such that today hematopoietic cell transplantation (HCT) from a matched unrelated donor (MUD) has been suggested as a possible first line strategy in pediatric patients with severe IAA, in the absence of a matched related donor. However, in this particular context, outcomes and early and long-term toxicities remain to be determined, as compared to non-transplant procedures. While prospective trials are ongoing, we report here the case of a 12-year-old boy with IAA, receiving an upfront bone marrow HCT from a MUD, who experienced early graft rejection associated with autologous hematological recovery, which could induce remission of his hemopathy. This case offers the opportunity to discuss the challenges associated with these new transplant paradigms and provides a brief review of the literature regarding the issue of autologous recoveries after allogeneic HCT in IAA.

A real-word experience of eltrombopag plus rabbit antithymocyte immunoglobulin-based IST in Chinese patients with severe aplastic anemia.

Eltrombopag (EPAG), a thrombopoietin receptor agonist, was approved for the treatment of severe aplastic anemia (SAA) combined with immunosuppressive therapy (IST). However, the effects of real-life use of low doses of EPAG combined with rabbit antithymocyte globulin (ATG)-based IST in Asian patients with SAA are yet unknown. A total of 121 previously untreated Chinese patients with SAA were enrolled in a multicenter registry of the Chinese Eastern Collaboration Group of Anemia (2014-2020): 67 patients received IST alone and 54 patients received additional EPAG. Patients receiving IST plus EPAG had a higher overall response rate (ORR) at 1 month (P = 0.002), 3 months (P = 0.028), 6 months (P = 0.006), and 12 months (P = 0.031) compared to those receiving IST alone. EPAG was the favorable factor for response efficacy at 6 months. The complete response rate in the EPAG plus IST group was 17% at 3 months, 27% at 6 months, and 32% at 12 months, compared to 7% (P = 0.069), 14% (P = 0.11), and 33% (P = 0.92) for those treated with IST alone. The 2-year overall survival rate in EPAG plus IST and IST alone groups was 98% and 88%, respectively (P = 0.078). The rate of adverse events, including clonal evolution, infection, and transaminitis, was similar in the two cohorts. The addition of EPAG to IST was well-tolerated and associated with high rates of hematologic responses among the previously untreated Chinese patients with SAA.

Comparable clinical outcomes of haploidentical hematopoietic stem cell transplantation in patients with hepatitis-associated aplastic anemia and non-hepatitis-associated aplastic anemia.

Hepatitis-associated aplastic anemia (HAAA), a rare subtype of aplastic anemia (AA), is defined as bone marrow failure occurring after acute hepatitis. Severe HAAA requires immunosuppressive therapy (IST) or hematopoietic stem cell transplantation (HSCT) as lifesaving treatment. The outcomes of HAAA patients who underwent haploidentical hematopoietic stem cell transplantation (haplo-HSCT) have not been systematically evaluated. We retrospectively compared the characteristics of 15 patients with HAAA and 60 non-hepatitis-associated aplastic anemia (non-HAAA) patients, all 75 of whom underwent haplo-HSCT in our hospital between January 2006 and October 2021. The median ages of the patients were 18 years old (range, 3-36) for HAAA patients and 13 years (range, 2-45) for non-HAAA patients (p = 0.693). The median time for neutrophil engraftment was 14 days (range, 11-22) in the HAAA group and 12 days (range, 10-21) in the non-HAAA group (p = 0.363). At the time of analysis, 15 HAAA patients and 58 non-HAAA patients were alive, and their median follow-up times were 37 (range, 3-87) months and 31 (range, 2-110) months (p = 0.347), respectively. There were no significant differences in the three-year overall survival (OS) rates (100% vs. 96.7 ± 0.33%, P = 0.638) or liver event-free survival (LEFS) (80.0 ± 0.17% vs. 76.7 ± 0.19%, P = 0.747) between the two groups. Despite the small number of HAAA patients due to the rarity of the disease, these results, such as the similar incidence rates of 3-year OS and fewer liver events than expected, suggest that haplo-HSCT is a feasible treatment for HAAA a when there are no human leukocyte antigen (HLA)-matched donors available and has a low risk of transplant-related mortality and complications.

A modified conditioning regimen based on low-dose cyclophosphamide and fludarabine for haploidentical hematopoietic stem cell transplant in severe aplastic anemia patients at risk of severe cardiotoxicity.

Severe cardiotoxicity is a fatal complication during high-dose cyclophosphamide (Cy)-based conditioning in hematopoietic stem cell transplant (HSCT) for severe aplastic anemia (SAA). This study aimed to evaluate the feasibility and efficacy of a modified conditioning regimen in haploidentical HSCT (haplo-HSCT) for severe-cardiotoxic-risk SAA patients. This BuCylow Flu conditioning utilized busulfan (Bu, 3.2 mg/kg for 2 days), low-dose Cy (100 mg/kg), fludarabine (150 mg/m2 ), and rabbit antithymocyte globulin (rATG, 10 mg/kg). Compared to BuCy conditioning using high-dose Cy of 200 mg/kg, Bu of 3.2 mg/kg for 2 days, and rATG of 10 mg/kg, the incidence of severe cardiotoxicity of BuCylow Flu conditioning was significantly decreased (2.17% vs 12.80%, p = .032). The engraftment rates (100% for neutrophil and 84.44% for platelet) were favorable. The probabilities of 100-day transplant-related mortality were similar in the BuCylow Flu and the BuCy group (8.75% vs 10.53%, p = .671). Both 1-year overall survival (88.79% vs 84.66%, p = .357) and 1-year failure-free survival (84.78% vs 81.70%, p = .535) were comparable. The BuCylow Flu group had higher rates of cytomegalovirus and Epstein-Barr virus reactivation. In conclusion, the BuCylow Flu provided reduced severe cardiotoxicity, and achieved favorable engraftment and survival. Our results suggest BuCylow Flu conditioning can be a feasible alternative for haplo-HSCT recipients at risk of severe cardiotoxicity.

Challenges in the interpretation of a germline TERT variant in a patient with juvenile myelomonocytic leukemia.

Dyskeratosis congenita (DC) is a bone marrow failure syndrome with extrahematopoietic abnormalities. DC is a paradigmatic telomere biology disorder (TBD) caused by germline mutations in genes responsible for telomere maintenance including TERT. Cryptic TBD is a bone marrow failure syndrome due to premature telomere shortening but without additional symptoms, frequently clinically indistinguishable from severe aplastic anemia (SAA) or hypoplastic myelodysplastic syndrome. We present the complex diagnostic pathway in a boy with a rare germline p.Thr726Met TERT variant with previous reports of SAA association and compromised enzymatic function who presented with juvenile myelomonocytic leukemia, which is a rare myelodysplastic/myeloproliferative neoplasm of childhood.

The impact of pretransplant serum ferritin on haploidentical hematopoietic stem cell transplant for acquired severe aplastic anemia in children and adolescents.

Haploidentical hematopoietic stem cell transplant (haplo-HSCT) provides an important alternative for children and adolescents with acquired severe aplastic anemia (SAA) lacking matched donors. To test whether pretransplant serum ferritin (SF) represents a candidate predictor for survival and a potential biomarker for graft-versus-host disease (GvHD) in pediatric haplo-HSCT, we retrospectively evaluated 147 eligible patients with SAA who underwent haplo-HSCT. The patients were divided into the low-SF group (< 1000 ng/mL) and the high-SF group (≥ 1000 ng/mL). We found that SF ≥1000 ng/mL independently increased the risk of grade II-IV aGvHD (HR = 2.596; 95% CI, 1.304-5.167, P = 0.007) and grade III-IV aGvHD (HR = 3.350; 95% CI, 1.162-9.658, P = 0.025). Similar probabilities of transplant-related mortality at 100 days were observed in the two groups (6.19 ± 2.45% vs 8.00 ± 3.84%, P = 0.168). The two-year overall survival (85.29 ± 3.89% vs 92.00% ± 3.84%, P = 0.746) and failure-free survival (83.23% ± 4.08% vs 83.37% ± 6.27%, P = 0.915) were comparable. GvHD-/failure-free survival were 60.06 ± 5.10% and 75.56 ± 6.87%, respectively (P = 0.056). In conclusion, elevated pretransplant SF level is associated with higher incidences of grade II-IV aGvHD and grade III-IV aGvHD. However, it is not associated with worse survival after haplo-HSCT for children and adolescent patients with SAA.

A Patient with Kabuki Syndrome Mutation Presenting with Very Severe Aplastic Anemia.

Kabuki syndrome (KS) is a rare congenital disorder commonly complicated by humoral immunodeficiency. Patients with KS present with mutation in the histone-lysine N-methyltransferase 2D (KMT2D) gene. Although various KMT2D mutations are often identified in lymphoma and leukemia, those encountered in aplastic anemia (AA) are limited. Herein, we present the case of a 45-year-old Japanese man who developed severe pancytopenia and hypogammaglobulinemia. He did not present with any evident malformations, intellectual disability, or detectable levels of autoantibodies. However, B-cell development was impaired. Therefore, a diagnosis of very severe AA due to a hypoplastic marrow, which did not respond to granulocyte colony-stimulating factor, was made. The patient received umbilical cord blood transplantation but died from a Pseudomonas infection before neutrophil engraftment. Trio whole-exome sequencing revealed a novel missense heterozygous mutation c.15959G >A (p.R5320H) in exon 50 of the KMT2D gene. Moreover, Sanger sequencing of peripheral blood and bone marrow mononuclear cells and a skin biopsy specimen obtained from this patient identified this heterozygous mutation, suggesting that de novo mutation associated with KS occurred in the early embryonic development. Our case showed a novel association between KS mutation and adult-onset AA.

Efficacy of hematopoietic stem cell transplantation in the treatment of children with non-severe aplastic anemia.

BACKGROUND: Non-severe aplastic anemia is more likely to develop into severe aplastic anemia, and there is no widely accepted treatment plan at present. Hematopoietic stem cell transplantation might be a new therapeutic strategy. METHODS: Retrospectively analyzed 32 patients with non-severe aplastic anemia who underwent hematopoietic stem cell transplantation from September 2007 to September 2020, and the 5-year estimated overall survival rate and the incidence of graft-versus-host disease were analyzed to evaluate the efficacy and safety of hematopoietic stem cell transplantation in the treatment of pediatric non-severe aplastic anemia. RESULTS: Thirty-two patients who underwent transplantation, 29 patients (90.6%) survived, 3 patients (9.4%) died. The incidence of acute graft-versus-host disease was 51.6% (16/31), including 15 cases (48.4%) of grade I-II and 1 case (3.2%) of grade III-IV. The incidence of chronic graft-versus-host disease was 38.7% (12/31). The 5-year overall survival rate was 91.8%. CONCLUSIONS: Hematopoietic stem cell transplantation is a practicable, safe, and effective treatment option for non-severe aplastic anemia pediatric patients who are suitable for transplant.

Identification of potential pathogenic genes for severe aplastic anemia by whole-exome sequencing.

BACKGROUND: Severe aplastic anemia (SAA) is a syndrome of severe bone marrow failure due to hyperfunction of CD8+ T cells. While, the genetic background of SAA is still unknown. In this study, we tried to explore the possible genetic variants in CD8+ T cells of SAA patients. METHODS: We performed whole-exome sequencing (WES) in CD8+ T cells of 4 SAA patients and 7 normal controls. The mutations that existed in SAA but not in NCs were identified as candidate genes. Then, we compared them with genes in the enriched KEGG pathway of differently expressed genes (DEGs) from previous RNA-seq. After analyzing the types of mutations, we identified possible pathogenic genes and validated them by RT-PCR. Finally, we compared them with the autoimmune disease-related genes in DisGeNET database to select the most possible pathogenic genes. RESULTS: We found 95 candidate mutant genes in which, 4 possible pathogenic genes were identified: PRSS1, KCNJ18, PRSS2, and DGKK. RT-PCR results showed that compared with NCs, PRSS1 and KCNJ18 mRNA expression was significantly increased in SAA patients (p < 0.05), PRSS2 was also increased in SAA patients but without statistical difference, and DGKK gene could not be detected by RT-PCR in SAA patients. In addition, PRSS1 was associated with autoimmune diseases from the DisGeNET database. CONCLUSION: The mutations of PRSS1, KCNJ18, PRSS2, and DGKK, especially PRSS1 in CD8+T cells, may be involved in the immune pathogenesis of SAA.

Abnormal expression of histone acetylases in CD8+ T cells of patients with severe aplastic anemia.

INTRODUCTION: We aimed to investigate the balance between the mRNA levels of histone acetyltransferases (HATs) and histone deacetylases (HDACs) in CD8+ T cells of patients with severe aplastic anemia (SAA). METHODS: Twenty untreated SAA patients, 18 remission SAA patients (R-SAA), and 22 normal controls were evaluated. The mRNA expression levels of HATs, HDACs, and IFNG in CD8+ T cells were measured by real-time quantitative reverse transcription polymerase chain reaction. RESULTS: Histone acetylase EP300 and CREBBP mRNA levels were significantly elevated in CD8+ T cells of SAA patients compared with the normal controls (both p < 0.05). No significant differences were observed in HDAC1 and HDAC7 mRNA between SAA patients and the normal controls. There was an obvious positive correlation between IFNG and EP300 (r = 0.5126, p < 0.01), and CREBBP (r = 0.4663, p < 0.05), respectively, in SAA and R-SAA patients. In addition, EP300 and CREBBP mRNA levels were clearly correlated with clinical parameters of peripheral blood and bone marrow in those patients. CONCLUSION: Our findings suggest that EP300 and CREBBP are increased in CD8+ T cells of SAA patients and are correlated with disease severity. The imbalances in HATs and HDACs may play a role in activating CD8+ T cells to promote the immune pathogenesis of SAA.