Long-Term Outcomes of Hematopoietic Stem Cell Transplantation for ZAP70 Deficiency

ZAP70 deficiency is a rare T?+?B?+?NK+ combined immunodeficiency with limited outcome data to help guide decisions around hematopoietic stem cell transplant (HSCT). We sought to understand the long-term clinical and immunologic outcomes of both conditioned and unconditioned HSCT for ZAP70 deficiency following transplant from a variety of graft sources. We performed a retrospective, single center review of all cases of HSCT for genetically confirmed ZAP70 deficiency since 1992. At a median of 13.5-year post-HSCT, 8/8 (100 %) patients are alive. Three received unconditioned bone marrow transplants from human leukocyte antigen (HLA)-matched siblings and achieved stable mixed donor-recipient T cell chimerism but low B cell (4–9 %) and absent to near-absent myeloid donor engraftment. Despite this, all three have normal immunoglobulin levels, have developed specific protective antibody responses to post-HSCT vaccinations, and have discontinued immunoglobulin replacement. Five patients received myeloablative conditioning (three T cell-depleted haploidentical and two unrelated cord blood) and have full donor chimerism for T and B cells and myeloid lineages. One patient experienced primary graft failure after serotherapy only. CD8 T cell count is normal in 5/8, high in 1/8, and low in 2/8. Infectious complications in 5/5 and autoimmune thrombocytopenia in one patient resolved post-HSCT. Mitogen proliferation to phytohemagglutinin was normal after HSCT in 8/8 patients. In total, seven have discontinued immunoglobulin replacement. In conclusion, HSCT using a variety of graft sources and approaches, including unconditioned matched sibling donor transplant, is a life-saving therapy for ZAP70 deficiency, providing excellent long-term immune function and resolution of clinical problems.     

Long-Term Immune Reconstitution and Infection Burden after Mismatched Hematopoietic Stem Cell Transplantation

Mismatched unrelated donor (MMUD) or umbilical cord blood (UCB) can be chosen as alternative donors for allogeneic stem cell transplantation but might be associated with long-lasting immune deficiency. Sixty-six patients who underwent a first transplantation from either UCB (n = 30) or 9/10 MMUD (n = 36) and who survived beyond 3 months were evaluated. Immune reconstitution was prospectively assessed at sequential time points after transplantation. NK, B, CD4⁺, and CD8⁺ T cells and their naïve and memory subsets, as well as regulatory T cells (Treg), were studied. Detailed analyses on infections occurring after 3 months were also assessed. The 18-month cumulative incidences of infection-related death were 8% and 3%, and of infections were 72% and 57% after MMUD and UCB transplantation, respectively. Rates of infection per 12 patient-month were roughly 2 overall (1 for bacterial, .9 for viral, and .3 for fungal infections). Memory, naïve CD4⁺ and CD8⁺T cells, naïve B cells, and Treg cells reconstitution between the 2 sources were roughly similar. Absolute CD4⁺T cells hardly reached 500 per μL by 1 year after transplantation and most B cells were of naïve phenotype. Correlations between immune reconstitution and infection were then performed by multivariate analyses. Low CD4⁺ and high CD8⁺T cells absolute counts at 3 months were linked to increased risks of overall and viral (but not bacterial) infections. When assessing for the naïve/memory phenotypes at 3 months among the CD4⁺ T cell compartment, higher percentages of memory subsets were protective against late infections. Central memory CD4⁺T cells protected against overall and bacterial infections; late effector memory CD4⁺T cells protected against overall, bacterial, and viral infections. To the contrary, high percentage of effector- and late effector-memory subsets at 3 months among the CD8⁺ T cell compartment predicted higher risks for viral infections. Patients who underwent transplantation from alternative donors represent a population with very high risk of infection. Detailed phenotypic analysis of immune reconstitution may help to evaluate infection risk and to adjust infection prophylaxis.     

Lineage-Specific Chimerism and Outcome After Hematopoietic Stem Cell Transplantation for DOCK8 Deficiency

Journal of Clinical Immunology - Bi-allelic variants in the dedicator of cytokinesis 8 (DOCK8) gene cause a combined immunodeficiency, characterized by recurrent sinopulmonary and skin infections,...     

Hematopoietic Stem Cell Transplantation for XIAP Deficiency in Japan

Background

X-linked inhibitor of apoptosis protein (XIAP) deficiency is a rare immunodeficiency that is characterized by recurrent hemophagocytic lymphohistiocytosis (HLH) and splenomegaly and sometimes associated with refractory inflammatory bowel disease (IBD). Although hematopoietic stem cell transplantation (HSCT) is the only curative therapy, the outcomes of HSCT for XIAP deficiency remain unsatisfactory compared with those for SLAM-associated protein deficiency and familial HLH.

Aim

To investigate the outcomes and adverse events of HSCT for patients with XIAP deficiency, a national survey was conducted.

Methods

A spreadsheet questionnaire was sent to physicians who had provided HSCT treatment for patients with XIAP deficiency in Japan.

Results

Up to the end of September 2016, 10 patients with XIAP deficiency had undergone HSCT in Japan, 9 of whom (90%) had survived. All surviving patients had received a fludarabine-based reduced intensity conditioning (RIC) regimen. Although 5 patients developed post-HSCT HLH, 4 of them survived after etoposide administration. In addition, the IBD associated with XIAP deficiency improved remarkably after HSCT in all affected cases.

Conclusion

The RIC regimen and HLH control might be important factors for successful HSCT outcomes, with improved IBD, in patients with XIAP deficiency.

     

Immune Reconstitution after Haploidentical Hematopoietic Stem Cell Transplantation

Haploidentical hematopoietic stem cell transplantation (HSCT) offers the benefits of rapid and nearly universal donor availability and has been accepted worldwide as an alternative treatment for patients with hematologic malignancies who do not have a completely HLA-matched sibling or who require urgent transplantation. Unfortunately, serious infections and leukemia relapse resulting from slow immune reconstitution remain the 2 most frequent causes of mortality in patients undergoing haploidentical HSCT, particularly in those receiving extensively T cell–depleted megadose CD34⁺ allografts. This review summarizes advances in immune recovery after haploidentical HSCT, focusing on the immune subsets likely to have the greatest impact on clinical outcomes. The progress made in accelerating immune reconstitution using different strategies after haploidentical HSCT is also discussed. It is our belief that a predictive immune subset–guided strategy to improve immune recovery might represent a future clinical direction.     

Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplantation for GATA2 Deficiency

We treated 14 patients with GATA2 deficiency using a nonmyeloablative allogeneic hematopoietic stem cell transplantation regimen. Four patients received peripheral blood stem cells from matched related donors (MRD), 4 patients received peripheral blood stem cells from matched unrelated donors (URD), 4 patients received hematopoietic stem cells from umbilical cord blood donors (UCB), and 2 patients received bone marrow cells from haploidentical related donors. MRD and URD recipients received conditioning with 3 days of fludarabine and 200 cGy total body irradiation (TBI). Haploidentical related donor recipients and UCB recipients received cyclophosphamide and 2 additional days of fludarabine along with 200 cGY TBI. MRD, URD, and UCB recipients received tacrolimus and sirolimus for post-transplantation immunosuppression, whereas haploidentical recipients received high-dose cyclophosphamide followed by tacrolimus and mycophenolate mofetil. Eight patients are alive with reconstitution of the severely deficient monocyte, B cell, and natural killer cell populations and reversal of the clinical phenotype at a median follow-up of 3.5 years. Two patients (1 URD recipient and 1 UCB recipient) rejected the donor graft and 1 MRD recipient relapsed with myelodysplastic syndrome after transplantation. We are currently using a high-dose conditioning regimen with busulfan and fludarabine in patients with GATA2 deficiency to achieve more consistent engraftment and eradication of the malignant myeloid clones.     

Long-Term Immune Reconstitution of Naive and Memory T Cell Pools after Haploidentical Hematopoietic Stem Cell Transplantation

Haploidentical hematopoietic stem cell transplantation (HSCT) constitutes an important alternative for patients lacking a human leukocyte antigen (HLA)-matched donor. Although the use of haploidentical donors is increasingly common, the long-term impact of generating a donor-derived immune system in the context of an HLA-mismatched thymic environment remains poorly characterized. We performed an in-depth assessment of immune reconstitution in a group of haploidentical HSCT recipients 4 to 6 years posttransplantation, in parallel with the respective parental donors and age-matched healthy control subjects. Our data show that the proportion of naive and memory subsets in the recipients, both within CD8⁺ and CD4⁺ T cells, more closely resembled that observed in age-matched control subjects than in the donors. HSCT recipients displayed relatively high signal-joint T cell–receptor excision circle levels and a high frequency of the recent thymic emigrant–enriched CD31⁺ subset within naive CD4⁺ and naive regulatory T cells. Moreover, CD8⁺, CD4⁺, and regulatory T cells from HSCT recipients displayed a diverse T cell repertoire. These results support a key role for thymic output in T cell reconstitution. Nevertheless, HSCT recipients had significantly shorter telomeres within a naive-enriched CD4⁺ T cell population than age-matched control subjects, despite the similar telomere length observed within the most differentiated CD8⁺ and CD4⁺ T cell subsets. Overall, our data suggest that long-term immune reconstitution was successfully achieved after haploidentical HSCT, a process that appears to have largely relied on de novo T cell production.     

Allogeneic Hematopoietic Stem Cell Transplantation for GATA2 Deficiency Using a Busulfan-Based Regimen

Allogeneic hematopoietic stem cell transplantation (HSCT) reverses the bone marrow failure syndrome due to GATA2 deficiency. The intensity of conditioning required to achieve reliable engraftment and prevent relapse remains unclear. Here, we describe the results of a prospective study of HSCT in 22 patients with GATA2 deficiency using a busulfan-based conditioning regimen. The study included 2 matched related donor (MRD) recipients, 13 matched unrelated donor (URD) recipients, and 7 haploidentical related donor (HRD) recipients. MRD and URD recipients received 4 days of busulfan and 4 days of fludarabine. HRD recipients received low-dose cyclophosphamide for 2 days, fludarabine for 5 days, 2 to 3 days of busulfan depending on cytogenetics, and 200 cGy total body irradiation. MRD and URD recipients received tacrolimus and short-course methotrexate for graft-versus-host disease (GVHD) prophylaxis. HRD recipients received high-dose post-transplant cyclophosphamide (PTCy) followed by tacrolimus and mycophenolate mofetil. At a median follow-up of 24 months (range, 9 to 50), 19 of 22 patients were alive with reversal of the disease phenotype and correction of the myelodysplastic syndrome, including eradication of cytogenetic abnormalities. Three patients died: 1 from refractory acute myelogenous leukemia, 1 from GVHD, and 1 from sepsis. There was a 26% incidence of grades III to IV acute GVHD in the MRD and URD groups and no grades III to IV acute GVHD in the HRD cohort. Similarly, there was a 46% incidence of chronic GVHD in the MRD and URD cohorts, whereas only 28% of HRD recipients developed chronic GVHD. Despite excellent overall disease-free survival (86%), GVHD remains a limitation using standard prophylaxis for GVHD. We are currently extending the use of PTCy to the MRD and URD cohorts to reduce GVHD.     

Aging Impairs Long-Term Hematopoietic Regeneration after Autologous Stem Cell Transplantation

Most of our knowledge of the effects of aging on the hematopoietic system comes from studies in animal models. In this study, to explore potential effects of aging on human hematopoietic stem and progenitor cells (HSPCs), we evaluated CD34⁺ cells derived from young (<35 years) and old (>60 years) adult bone marrow with respect to phenotype and in vitro function. We observed an increased frequency of phenotypically defined stem and progenitor cells with age, but no distinct differences with respect to in vitro functional capacity. Given that regeneration of peripheral blood counts can serve as a functional readout of HSPCs, we compared various peripheral blood parameters between younger patients (≤50 years; n = 64) and older patients (≥60 years; n = 55) after autologous stem cell transplantation. Patient age did not affect the number of apheresis cycles or the amount of CD34⁺ cells harvested. Parameters for short-term regeneration did not differ significantly between the younger and older patients; however, complete recovery of all 3 blood lineages at 1 year after transplantation was strongly affected by advanced age, occurring in only 29% of the older patients, compared with 56% of the younger patients (P = .009). Collectively, these data suggest that aging has only limited effects on CD34⁺ HSPCs under steady-state conditions, but can be important under consitions of chemotoxic and replicative stress.     

Study of Kidney Function Impairment after Reduced-Intensity Conditioning Allogeneic Hematopoietic Stem Cell Transplantation. A Single-Center Experience

Acute renal failure (ARF) is a life-threatening complication after allogeneic stem cell transplantation (Allo-HSCT). Identification of ARF risk factors could be useful to develop preventive strategies for patients at high risk. The goal of this study was to evaluate the incidence and risk factors of ARF after reduced intensity conditioning Allo-HSCT (Allo-RIC). We included 188 consecutive patients who underwent Allo-RIC in our center between January 1999 and December 2006. ARF was defined as a decrease of at least 25% in baseline estimated glomerular filtration rate (GFR) calculated by modification of diet in renal disease (MDRD) equation. Conditioning consisted of fludarabine (Flu) 150 mg/m² in combination with busulfan (Bu) 8-10 mg/kg (n = 61), melphalan (Mel) 140 mg/m² (n = 115), cyclophosphamide (Cy) 120 mg/kg (n = 7) or low-dose total-body irradiation (TBI) 2 Gy (n = 5). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine A (CsA) alone (n = 3) or in addition to methotrexate (MTX; n = 132) or mycophenolate mofetil (MMF; n = 51). The cumulative incidence of ARF at 1 year was 52% (n = 97 patients) after Allo-RIC. Most cases (86%) occurred within the first 3 months, and the main cause was the administration of CsA (71%). The risk factors associated with ARF in multivariate analysis were: administration of MTX (hazard ratio [HR] 1.9, P =.02), more than 3 lines of therapy prior to Allo-RIC (HR 1.8, P = .01), diabetes mellitus (HR 2.1, P < .01), and GVHD grade III-IV (HR 2.1, P = .015). In multivariate analysis, ARF was an independent risk factor for 1-year nonrelapse mortality (NRM) (HR 3, 95% confidence interval [CI]: 1.5-6, P = .002). Patients who experienced ARF had lower 1-year overall survival (OS; 53% versus 74%, P < .05). ARF is a frequent complication in patients after Allo-RIC, and it has a negative impact on outcome. Identification of ARF risk factors could help to avoid exposure to nephrotoxic drugs during the follow-up in patients at high risk.     

Multicenter Experience of Hematopoietic Stem Cell Transplantation in WHIM Syndrome

Journal of Clinical Immunology - WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is a rare disease, caused by CXCR4 gene mutations, which incorporates features of...     

Hematopoietic Stem Cell Transplantation for Shwachman-Diamond Syndrome

We report the outcomes of hematopoietic stem cell transplantation (HSCT) for 52 patients with Shwachman-Diamond syndrome (SDS) who underwent transplantation between 2000 and 2017. The median age at transplantation was 11 years, and the median duration of follow-up was 60 months. The indication for HSCT was bone marrow failure (BMF; cytopenia or aplastic anemia) in 39 patients and myelodysplasia (MDS)/acute myelogenous leukemia (AML) in 13 patients. The donor type was an HLA-matched sibling for 18 patients, an HLA-matched or mismatched relative for 6 patients, and an HLA-matched or mismatched unrelated donor for 28 patients. Preparative regimens for BMF were myeloablative in 13 patients and reduced intensity in 26. At the time of this report, 29 of the 39 patients with BMF were alive, and the 5-year overall survival was 72% (95% confidence interval, 57% to 86%). Graft failure and graft-versus-host disease were the predominant causes of death. Preparative regimens for patients with MDS/AML were myeloablative in 8 and reduced intensity in 5. At the time of this report, only 2 of 13 patients were alive (15%), with relapse the predominant cause of death. Survival after transplantation for SDS-related BMF is better compared with historical reports, but strategies are needed to overcome graft failure and graft-versus-host disease. For SDS- related MDS or AML, transplantation does not extend survival. Rigorous surveillance and novel treatments for leukemia are urgently needed.