Primary immunodeficiencies are congenital genetically determined immune disorders. Recent advances in molecular genetic technologies have enabled a simultaneous analysis of a large number of genes in a patient. The purpose of this study was to analyze the mutational spectrum in DNA samples collected from patients with various types of primary immunodeficiencies. In this study, we applied next-generation sequencing technology using a panel developed at the Belarusian Research Center for Pediatric Oncology, Hematology and Immunology and consisting of 290 genes that are associated with primary immunodeficiencies according to the existing literature. The testing was carried out in 96 patients with a clinical history suggesting a primary immunological defect. As a result, 37.5% of cases (36/96 patients) were found to harbor genetic defects that lead to disorders of the immune system.
Partial leukocyte adhesion deficiency type 1 (LAD-1) deficiency is extremely rare condition with milder infectious manifestation and immune system imbalance leads to increased risks of autoinflammatory complications, such as pyoderma gangrenosum, that can be triggered by trauma or pregnancy. In patients with spice-site ITGB2 variants, partial expression can occur due to different β2 integrin isophorms expression.
Patients with hypomorphic mutations in the RAG1 or RAG2 gene present with either Omenn syndrome or atypical combined immunodeficiency with a wide phenotypic range. Hematopoietic stem cell transplantation (HSCT) is potentially curative, but data are scarce. We report on a worldwide cohort of 60 patients with hypomorphic RAG variants who underwent HSCT, 78% of whom experienced infections (29% active at HSCT), 72% had autoimmunity, and 18% had granulomas pretransplant. These complications are frequently associated with organ damage. Eight individuals (13%) were diagnosed by newborn screening or family history. HSCT was performed at a median of 3.4 years (range 0.3-42.9 years) from matched unrelated donors, matched sibling or matched family donors, or mismatched donors in 48%, 22%, and 30% of the patients, respectively. Grafts were T-cell depleted in 15 cases (25%). Overall survival at 1 and 4 years was 77.5% and 67.5% (median follow-up of 39 months). Infection was the main cause of death. In univariable analysis, active infection, organ damage pre-HSCT, T-cell depletion of the graft, and transplant from a mismatched family donor were predictive of worse outcome, whereas organ damage and T-cell depletion remained significant in multivariable analysis (hazard ratio [HR] = 6.01, HR = 8.46, respectively). All patients diagnosed by newborn screening or family history survived. Cumulative incidences of acute and chronic graft-versus-host disease were 35% and 22%, respectively. Cumulative incidences of new-onset autoimmunity was 15%. Immune reconstitution, particularly recovery of naïve CD4+ T cells, was faster and more robust in patients transplanted before 3.5 years of age, and without organ damage. These findings support the indication for early transplantation.
X-linked lymphoproliferative disease type I (XLP I) is caused by mutations in the SH2D1A gene and characterized mainly by hypogammaglobulinemia and abnormal response to Epstein-Barr virus with a high predisposition to B-cell non-Hodgkin lymphoma development.In this article, we describe the experience of 2 centers in Belarus and in Russia that follow 3 male patients who were diagnosed with XLP I after lymphoma development and treatment. Three novel mutations c.51G>C (p.E17D), c.192G>T (p.W64C), and c.53insA (p.K18KfsX67) were found in 3 males patients with XLP I. Two of them did not have any signs of immunodeficiency before B-cell non-Hodgkin lymphoma development.We propose SH2D1A mutational screening be considered in male patients with or without hypogammaglobulinemia who received rituximab treatment for lymphoma and did not recover immunoglobulin G in a year after B-depleting therapy.
Six boys aged from 4 months to 15 years old were diagnosed with Wiskott-Aldrich syndrome in the Republican Research Centre for Pediatric Oncology and Hematology. All the patients revealed WAS gene mutations. The missence-mutations in exones 2 and 3, detected in 4 patients prevailed in the spectrum of the mutations. WASP was fully absent in lymphocytes and rather a severe course of the disease was observed in all the patients. Only one child with WAS gene mutation in second exone had a mild course of the disease. The mutations were localized in tenth exone in two patients, which is a nonsense of the mutation. The WASP expression was partially preserved in one patient with such mutation.