Successful Haematopoietic Stem Cell Transplantation for LRBA Deficiency with Fludarabine, Treosulfan, and Thiotepa-Based Conditioning.

LRBA deficiency is an inborn error of immunity defined by autoimmunity, lymphoproliferation, recurrent infections, cytopenia, and inflammatory bowel disease. Despite recent advances in managing this disease with targeted biologic therapy, haematopoietic stem cell transplant (HSCT) remains the only cure. However, great variability exists between protocols used to transplant patients with LRBA deficiency. We describe a cohort of seven patients with LRBA deficiency who underwent HSCT using a myeloablative, reduced toxicity regime of fludarabine, treosulfan, and thiotepa at two transplantation centres from 2016 to 2019. Data were collected both retrospectively and prospectively, measuring time to engraftment, infectious complications, incidence of graft versus host disease, and post-transplantation chimerism. Six of seven patients survived transplantation, and four of six surviving patients achieving treatment-free survival. We thus recommend that HSCT with fludarabine, treosulfan, and thiotepa-based conditioning be considered in patients with LRBA deficiency.

Biallelic Loss of Function Variants in SENP7 Cause Immunodeficiency with Neurologic and Muscular Phenotypes.

To evaluate a novel candidate disease gene, we engaged international collaborators and identified rare, biallelic, specifically homozygous, loss of function variants in SENP7 in 4 children from 3 unrelated families presenting with neurodevelopmental abnormalities, dysmorphism, and immunodeficiency. Their clinical presentations were characterized by hypogammaglobulinemia, intermittent neutropenia, and ultimately death in infancy for all 4 patients. SENP7 is a sentrin-specific protease involved in posttranslational modification of proteins essential for cell regulation, via a process referred to as deSUMOylation. We propose that deficiency of deSUMOylation may represent a novel mechanism of primary immunodeficiency.

Two decades of stem cell transplantation in patients with Fanconi anemia: Analysis of factors affecting transplant outcomes.

Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for the hematological complications of patients with Fanconi anemia (FA). Over the last two decades, HSCT outcomes have improved dramatically following the development of regimens tailored for FA patients. In this study, we analyzed genetic, clinical, and transplant data of 41 patients with FA who underwent HSCT at Hadassah Medical Center between November 1996 and September 2020. Overall survival (OS) was 82.9% with a median follow-up time of 2.11-years (95% CI, .48-16.56). Thirteen patients (31.7%) developed acute graft-versus-host disease (GVHD), three of them with grades 3-4. Nine patients developed chronic GVHD, five had extensive disease. Twelve patients (29.3%) developed stable mixed-chimerism with complete resolution of bone marrow failure (BMF); none of them had acute nor chronic GVHD. Significantly higher GVHD rates were observed in transplants from peripheral blood stem cell grafts as compared to other stem cell sources (p = .002 for acute and p = .004 for chronic GVHD). Outcome parameters were comparable between HSCT from matched-sibling (n = 20) to other donors (n = 21), including survival rates (p = .1), time to engraftment (p = .69 and p = .14 for neutrophil and platelet engraftment time, respectively), chimerism status (p = .36 and p = .83 for full-donor and mixed chimerism, respectively), and GVHD prevalence (p = 1). Our results demonstrate the vast improvements in HSCT outcomes of patients with FA, narrowing the gap between matched-sibling versus alternative donor transplantations. Our data identifies factors that may significantly affect transplant outcomes such as graft source and chimerism status.

The Broad Clinical Spectrum and Transplant Results of PNP Deficiency.

PURPOSE: Purine nucleoside phosphorylase (PNP) is a known yet rare cause of combined immunodeficiency with a heterogeneous clinical presentation. We aim to add to the expanding clinical spectrum of disease, and to summarize the available data on bone marrow transplant for this condition. METHODS: Data was collected from patient files retrospectively. A review of the literature of hematopoietic stem cell transplantation (HSCT) for PNP deficiency was conducted. RESULTS: Four patients were treated in two centers in Israel. One patient died of EBV-related lymphoma with CNS involvement prior to transplant. The other three patients underwent successful HSCT with good immune reconstitution post-transplant (follow-up 8-108 months) and excellent neurological outcomes. CONCLUSION: PNP is a variable immunodeficiency and should be considered in various clinical contexts, with or without neurological manifestations. HSCT offers a good treatment option, with excellent clinical outcomes, when preformed in a timely manner.

Autoimmune Cytopenias Post Hematopoietic Stem Cell Transplantation in Pediatric Patients With Osteopetrosis and Other Nonmalignant Diseases.

Autoimmune cytopenia (AIC) is a rare complication post hematopoietic stem cell transplantation (HSCT), with a higher incidence in nonmalignant diseases. The etiology of post-HSCT AIC is poorly understood, and in many cases, the cytopenia is prolonged and refractory to treatment. Diagnosis of post-HSCT AIC may be challenging, and there is no consensus for a standard of care. In this retrospective study, we summarize our experience over the past five years with post-HSCT AIC in pediatric patients with osteopetrosis and other nonmalignant diseases. All pediatric patients who underwent HSCT for nonmalignant diseases at Hadassah Medical Center over the past five years were screened for post-HSCT AIC, and data were collected from the patient's medical records. From January 2017 through December 2021, 140 pediatric patients underwent HSCT for osteopetrosis (n=40), and a variety of other nonmalignant diseases. Thirteen patients (9.3%) presented with post-HSCT AIC. Of these, 7 had osteopetrosis (17.5%), and 6 had other underlying nonmalignant diseases. Factors associated with developing AIC included unrelated or non-sibling family donors (n=10), mixed chimerism (n=6), and chronic GvHD (n=5). Treatment modalities included steroids, IVIG, rituximab, bortezomib, daratumumab, eltrombopag, plasmapheresis, and repeated HSCT. Response to treatment was variable; Seven patients (54%) recovered completely, and three patients (23%) recovered partially, still suffering from mild-moderate thrombocytopenia. Three patients died (23%), two following progressive lung disease and one from sepsis and multi-organ failure after a 3rd HSCT. In our experience, post-HSCT AICs in pediatric patients with nonmalignant diseases may pose a challenging post-transplant complication with a variable presentation and a wide spectrum of severity. A relatively high prevalence is seen in patients with osteopetrosis, possibly due to difficult engraftment and high rates of mixed chimerism. There is a dire need for novel treatment modalities for better management of the more severe and refractory cases.

A human case of GIMAP6 deficiency: a novel primary immune deficiency.

The GTPase of immunity-associated proteins (GIMAPs) are a family of genes believed to contribute to lymphocyte development, signaling, and apoptosis, thus playing an important role in immune system homeostasis. While models of gene derangement have been described in both mice and immortalized cell lines, human examples of these diseases remain exceptionally rare. In this manuscript we describe the first documented human cases of a homozygous deleterious GIMAP6 variant in the GIMAP6 gene and their subsequent clinical and immunological phenotype. In order to interrogate the patients' immune defect, we performed whole-exome sequencing, western blot, flow cytometry analysis, lymphocyte activation and proliferation studies, cytokine release assays, and apoptosis studies. We found two siblings with a predicted deleterious homozygous variant in the GIMAP6 gene with no expression of GIMAP6 protein on western blot. Patients demonstrated accelerated apoptosis, but largely normal lymphocyte subpopulations, activation and proliferation and cytokine release. There appears to be a spectrum of clinical features associated with deficiency of GIMAP6 protein, with one patient suffering lymphopenia and recurrent sinopulmonary infections, and the other clinically asymptomatic. Biallelic variants in the GIMAP6 gene have now been shown to demonstrate disease in humans. The absence of GIMAP6 protein is associated with a spectrum of clinical manifestations and much remains to be learnt about the pathogenic mechanisms underlying this disease. We suggest that biallelic variants in the gene for GIMAP6 should be considered in children with lymphopenia and recurrent sinopulmonary infections.

Characteristics of patients with sulphonurea-induced hypoglycemia.

BACKGROUND/AIM: Sulphonylurea (SU) agents continue to be a cornerstone of the therapy of type 2 diabetes mellitus (T2DM). Hypoglycemia is the most dangerous side effect of SU. Identifying the characteristics of patients with SU-induced hypoglycemia (SUIH) may help in reducing its frequency. METHODS: All consecutive admissions of patients with SUIH, between 2000 and 2008, were retrospectively reviewed. RESULTS: Over the study period, 4702 patients with type 2 diabetes mellitus were admitted to the department of medicine. Of these, 155 patients were admitted because of SUIH. Most of these patients were elderly, had multiple comorbid situations, and were taking multiple medications. Almost a third of the patients had a history of recent changes in the use of their medications. Various infectious complications (urinary, lung, skin, and peritoneal) occurred in 43% of patients. Renal failure was a frequent finding at admission (44% of patients had creatinine plasma levels > 120 µmol/L). Poor oral intake before admission was reported by 31% of patients. Markers of malnutrition (low serum levels of albumin, iron, vitamin B-12, and folic acid) were frequently found in most patients. Mean hemoglobin A1C levels were in the low abnormal levels. A major vascular event during hospitalization co-occurred in 11% of patients. Three patients died during the hospital admission for SUIH. CONCLUSIONS: Elderly fragile patients with multiple comorbid situations including renal failure and tight glycemic control are prone to develop SUIH. Sulphonylurea agents should be avoided in such patients. An episode of SUIH should be considered as an alarming prognostic marker.