Long-term outcomes of fludarabine, melphalan and antithymocyte globulin as reduced-intensity conditioning regimen for allogeneic hematopoietic stem cell transplantation in children with primary immunodeficiency disorders: a prospective single center study

Clinical and immunological characteristics of 69 leukocyte adhesion deficiency-I patients

BACKGROUND

In order to support the comprehensive classification of Leukocyte Adhesion Deficiency-I (LAD-I) severity by simultaneous screening of CD11a/CD18, this study assessed clinical, laboratory, and genetic findings along with outcomes of 69 LAD-I patients during the last 15 years.

METHODS

Sixty-nine patients (40 females and 29 males) with a clinical phenotype suspected of LAD-I were referred to Immunology, Asthma, and Allergy research institute, Tehran, Iran between 2007 and 2022 for further advanced immunological screening and genetic evaluations as well as treatment, were enrolled in this study.

RESULTS

The diagnosis median age of the patients was 6 months. Delayed umbilical cord separation was found in 25 patients (36.2%). The median diagnostic delay time was 4 months (min-max: 0-82 months). Forty-six patients (66.7%) were categorized as severe (CD18 and/or CD11a: below 2%); while 23 children (33.3%) were in moderate category (CD18 and/or CD11a: 2%-30%). During the follow-ups, 55.1% of children were alive with a mortality rate of 44.9%. Skin ulcers (75.4%), omphalitis (65.2%), and gingivitis (37.7%) were the most frequent complaints. Genetic analysis of the patients revealed 14 previously reported and three novel pathogenic mutations in the ITGB2 gene. The overall survival of patients with and without hematopoietic stem cell transplantation was 79.3% and 55.6%, respectively.

CONCLUSION

Physicians' awareness of LAD-I considering delayed separation of umbilical cord marked neutrophilic leukocytosis, and variability in CD11 and CD18 expression levels, and genetic analysis leads to early diagnosis and defining disease severity. Moreover, the prenatal diagnosis would benefit families with a history of LAD-I.

Escalated Dose Donor Lymphocyte Infusion Treatment in Patients with Primary Immune Deficiencies After HSCT with Reduced-Intensity Conditioning Regimen

OBJECTIVE/BACKGROUND

Mixed chimerism is a major concern after allogenic hematopoietic stem cell transplantation (HSCT) using a reduced-intensity conditioning (RIC) regimen in primary immunodeficiencies (PIDs). A donor lymphocyte infusion (DLI) escalating dose regimen has been developed with the aim of reducing toxicity while preserving efficacy. However, the graft-versus-host disease (GvHD) development remains the most common and adverse effect of DLI and continues to be a limiting factor in its application, especially nonmalignant diseases such as PIDs. We prospectively evaluated PID patients after HSCT using RIC in Childrens Medical Center, who were candidates for an escalating dose of DLI for MC from 2016 to 2018.

METHODS

With the median follow-up of 16.4 months, 12 patients (nine males and three females) with a median age of 3.72 years received DLI. The median number of DLI was 3.2 (range, 1-5), the maximum and total dose of DLIs administered per patient were 3.6 × 10⁷ (range, 1-5) cells/kg CD3⁺ and 9.3 × 10⁷ (range, 1-15) cells/kg CD3⁺ cells, respectively.

RESULTS

Median donor chimerism at baseline before the DLIs was 41% (range, 11-73%), patients received DLIs at a median of 105 (range, 37-230) days and 52 (range, 3-168) days after the HSCT and onset of the MC, respectively. At the final assessment, six (54.5%) patients improved after DLIs at a median of 47.3 days.

CONCLUSION

PID patients may benefit from DLI with an escalating dose regimen, but the GvHD development remains a concern during the DLI, and the optimum dose and frequency must be standardized.

Fludarabine-based Reduced Intensity Conditioning for Allogeneic Hematopoietic Stem Cell Transplantation in a Pediatric Patient With Bone Marrow Failure Syndrome Type 3

Bone marrow failure syndrome (BMFS) type 3 is a rare genetic heterogeneous disorder, considered to be one of Inherited BMFSs related to ribosomopathies. It caused by a novel Homozygous variant in DNAJC21 gene, which affects cytoplasmic maturation of 60S ribosomal, leading to increase cell death, and inhibits cellular proliferation causing shwachman-diamond Syndrome-like syndrome. Only 15 cases of BMFS type 3 have been published in the literature. Therefore, the full phenotypic spectrum and the experience of hematopoietic stem cell transplantation (HSCT) are limited. Herein, we report an uncomplicated HSCT from human leukocyte antigen-identical sibling for a BMFS-3 patient at 22 months of age, who suffered from chronic diarrhea, severe failure to thrive and cytopenia required transfusions. We used a reduced intensity conditioning regimen including fludarabine, low-dose cyclophosphamide, and antithymocyte globulin with cyclosporine for prevent graft versus host disease. This regimen was safe and sufficient to achieve rapid engraftment without significant toxicity. Although, Mixed chimerism between 80% and 90% was observed since day +30, she gained 2 kg during 12 months post-transplant and no need for transfusions has been reported any more. Thus, we recommend HSCT with fludarabine-based reduced intensity conditioning regimen in this syndrome as progressive cytopenia occurs and an human leukocyte antigen-matched family donor is available.

Conditioning regimens for inborn errors of immunity: current perspectives and future strategies

Inborn errors of immunity (IEI) are caused by germline genetic mutations, resulting in defects of innate or acquired immunity. Hematopoietic cell transplantation (HCT) is indicated for curative therapy especially in patients with IEI who develop fatal opportunistic infections or severe manifestations of immune dysregulation. The first successful HCT for severe combined immunodeficiency (SCID) was reported in 1968. Since then, the indications for HCT have expanded from SCID to various non-SCID IEI. In general, HCT for IEI differs from that for other hematological malignancies in that the goal is not to eradicate certain immune cells but to achieve immune reconstitution. European Society for Blood and Marrow Transplantation/European Society for Immunodeficiencies guidelines recommend reduced-intensity conditioning to avoid treatment-related toxicity, and the optimal conditioning regimen should be considered for each IEI. We review conditioning regimens for some representative IEI disorders in Japanese and worldwide cohort studies, and future strategies for treating IEI.

Donor-Host Lineage-Specific Chimerism Monitoring and Analysis in Pediatric Patients Following Allogeneic Stem Cell Transplantation: Influence of Pretransplantation Variables and Correlation with Post-Transplantation Outcomes

The impact of donor-host chimerism in post-hematopoietic stem cell transplantation (HSCT) outcomes is poorly understood. We were interested in studying whether pre-HSCT variables influenced lineage-specific donor-host chimerism and how lineage-specific chimerism impacts post-HSCT outcomes. Our main objective was to study pre-HSCT variables as predictors of lineage-specific donor-host chimerism patterns and to better characterize the relationship between post-HSCT lineage-specific chimerism and adverse outcomes, including graft failure and disease relapse. We conducted a retrospective data analysis of all patients who underwent allogeneic HSCT at the Pediatric Transplantation and Cellular Therapy service at Memorial Sloan Kettering Cancer Center between January 2010 and June 2015 and had at least 2 measurements of split-lineage chimerism. The trend of lineage-specific donor-host chimerism post-HSCT and the impact of age, disease, graft type, and pretransplantation conditioning regimen on chimerism at 3 months and 12 months post-HSCT were studied. The Wilcoxon signed-rank test, Mann-Whitney-Wilcoxon test, and Cox proportional hazard models were used for statistical analyses. A total of 137 patients were included (median age, 11.3 years). Most patients had a hematologic malignancy (n = 95), and fewer had a nonmalignant disorder (n = 27) or primary immune deficiency (n = 15). Myeloablative conditioning regimens (n = 126) followed by T cell-depleted (TCD) peripheral blood stem cell or bone marrow grafts (n = 101) were most commonly used. Mixed chimerism (MC) of total peripheral blood leukocytes (PBLs) did not predict loss of donor chimerism in all lineages and when stable was not associated with graft failure or rejection in this analyses. Split chimerism with complete donor chimerism (CC) of myeloid, B, and natural killer cells, but not T cells, occurred early post-HSCT, but full donor T cell chimerism was achieved at 12 months post-HSCT by most patients. MC within the T cell lineage was the major contributor to PBL MC, with lower median donor T cell chimerism at 3 months than at 12 months (91%) post-HSCT (51% versus 91%; P < .0001). Predictors of MC at 3 and 12 months were (1) age <3 years (P = .01 for PBLs and P = .003 for myeloid lineage); (2) nonmalignant disorder (P = .007 for PBLs); and (3) the use of reduced-intensity conditioning regimens. TCD grafts produced lower donor T cell chimerism at 3 months post-HSCT compared with unmodified grafts (P < .0001), where T cell lineage CC was achieved early post-HSCT. The donor T cell chimerism was similar at 12 months in the 2 types of grafts. Umbilical cord blood grafts had CC in all lineages at all time points post-HSCT. Loss of donor B cell chimerism was associated with increased risk of relapse in hematologic malignancies (hazard ratio, 1.33; P = .05). Age, underlying disease, conditioning regimen, and graft manipulation can impact post-HSCT donor-host chimerism and be predictors for early MC. MC in total PBLs and T cells was not related to graft failure or disease relapse. Whole-blood PBL chimerism analysis is not sufficient to assess the significance of post-HSCT donor-host status; rather, lineage-specific chimerism, particularly for myeloid, T, and B cells, should be analyzed to guide interventions and inform outcomes.

Fludarabine-based reduced-intensity conditioning regimen for hematopoietic stem cell transplantation in pediatric patient with IL10 receptor deficiency

IL-10R deficiency results in severe immune dysregulation. Herein, we describe the successful treatment of a girl aged 6.8 years with IL10R deficiency by using RIC prior to HSCT from a matched unrelated donor. The regimen was well tolerated, the engraftment was completely attained. On a follow-up of 7 months, the patient remained in good medical conditions with full donor chimerism. All complications before HSCT were completely resolved and her growth was accelerated. RIC regimen might be adequate to induce permanent engraftment and avoid severe organ toxicity in IL-10R deficiency patients.

Hematopoietic Cell Transplantation with Reduced Intensity Conditioning Using Fludarabine/Busulfan or Fludarabine/Melphalan for Primary Immunodeficiency Diseases

PURPOSE

The purpose of our study was to compare the safety and efficacy of hematopoietic cell transplantation (HCT) using fludarabine (Flu)-based reduced intensity conditioning (RIC) with busulfan (BU) or melphalan (Mel) for primary immunodeficiency diseases (PID).

METHODS

We retrospectively analyzed transplant outcome, including engraftment, chimerism, immune reconstitution, and complications in 15 patients with severe combined immunodeficiency (SCID) and 27 patients with non-SCID PID. The patients underwent Flu-based RIC-HCT with BU (FluBU: 7 SCID, 16 non-SCID) or Mel (FluMel: 8 SCID, 11 non-SCID). The targeted low-dose BU with therapeutic drug monitoring was set to 30 mg hour/L for SCID.

RESULTS

The 2-year overall survival of all patients was 79.6% and that of patients with SCID in the FluBU and FluMel groups was 100% and 62.5%, respectively. In the FluBU group, all seven patients achieved engraftment, good immune reconstitution, and long-term survival. All five patients receiving umbilical cord blood transplantation achieved complete or high-level mixed chimerism and sufficient specific IgG production. In the FluMel group, six of eight patients achieved complete or high-level mixed chimerism. Viral reactivation or new viral infection occurred in one FluBU group patient and four FluMel group patients. In the non-SCID group, 10 of 11 patients (91%) who received FluMel achieved complete or high-level mixed chimerism but had variable outcomes. Patients with WAS (2/2 patients), NEMO deficiency (2/2 patients), and X-linked hyper IgM syndrome (2/3 patients) who received FluBU achieved complete or high-level mixed chimerism and long-term survival.

CONCLUSIONS

RIC-HCT with FluBU is a safe and effective strategy for obtaining high-level donor chimerism, immune reconstitution including B cell function, and long-term survival in patients with SCID. In patients with non-SCID PID, the results varied according to the subtype of the disease. Further prospective studies are required to optimize the conditioning regimen for non-SCID PID.

Successful Reduced Intensity Conditioning Alternate Donor Stem Cell Transplant for Wiskott-Aldrich Syndrome

There are very few reports of reduced intensity conditioning (RIC) hematopoietic stem cell transplant (HSCT) with alternate donor for Wiskott-Aldrich syndrome (WAS) and there is no report of RIC with posttransplant cyclophosphamide (PTCy) in WAS. There is only 1 report of T cell receptor αβ and CD19-depleted haploidentical HSCT for WAS. Here we report successful outcome in 3 children with WAS who underwent successful RIC alternate donor HSCT of whom 2 (matched unrelated donor and T-cell replete haploidentical) received PTCy and 1 underwent T cell receptor αβ and CD19-depleted haploidentical HSCT. We modified conditioning used by Luznik for haploidentical HSCT by adding thiotepa 8 mg/kg and Campath or rabbit antithymoglobulin for 2 cases who received PTCy. In third case we gave fludarabine, thiotepa, and treosulfan-based conditioning. The mean duration of follow-up for these patients was 23.6 months posttransplant (range, 21 to 26 mo). All 3 patients are transfusion independent. Acute graft versus host disease (GVHD) grade I occurred in 1 and none had chronic GVHD. Chimerism of all 3 was fully donor (>95% donor) at D+30 and D+100 posttransplant. All are alive, healthy, and doing well. Our 3 cases highlight that with newer conditioning and GVHD prophylaxis approach alternate donor HSCT in WAS can become a safe and effective treatment option.

Haematopoietic stem cell transplantation for primary immunodeficiency syndromes: A 5-year single-centre experience

AIM

Haematopoietic stem cell transplantation (HSCT) is a central therapy in the treatment of primary immunodeficiency diseases (PIDs). Over the past 5 years, outcomes have been greatly improved due to earlier diagnosis, improved donor availability, advancements in graft manipulation and the use of less toxic preparative regimens. We present a 5-year audit of HSCT for PID at a single Australian tertiary hospital.

METHODS

Retrospective case note review identified diagnosis, pre-transplant medical morbidity, transplant protocol, engraftment, adverse events, post-transplant immune reconstitution and general health.

RESULTS

A total of 22 patients with PID underwent 24 HSCTs at our institution between 2012 and 2016. The most common indications were severe combined immunodeficiency, chronic granulomatous disease and familial haemophagocytic lymphohistiocytosis, with a genetic diagnosis in all but two patients. Reduced intensity or reduced toxicity conditioning was used in 91% of cases, and 75% of the donors were unrelated. Transplant-related mortality at day +100 was 9.5%, and cumulative overall survival was 86%. There were three mortalities, all secondary to viral infection, one of which occurred in the context of graft failure. Two patients remained on immune support, with the remainder achieving adequate immune reconstitution.

CONCLUSIONS

The outcomes for HSCT for PIDs performed at Sydney Children's Hospital were in line with the world's best practice. HSCT should be considered a potential therapeutic option for all Australian PID patients with a valid disease indication.