Partial RAG deficiency in humans induces dysregulated peripheral lymphocyte development and humoral tolerance defect with accumulation of T-bet+ B cells.

The recombination-activating genes (RAG) 1 and 2 are indispensable for diversifying the primary B cell receptor repertoire and pruning self-reactive clones via receptor editing in the bone marrow; however, the impact of RAG1/RAG2 on peripheral tolerance is unknown. Partial RAG deficiency (pRD) manifesting with late-onset immune dysregulation represents an 'experiment of nature' to explore this conundrum. By studying B cell development and subset-specific repertoires in pRD, we demonstrate that reduced RAG activity impinges on peripheral tolerance through the generation of a restricted primary B cell repertoire, persistent antigenic stimulation and an inflammatory milieu with elevated B cell-activating factor. This unique environment gradually provokes profound B cell dysregulation with widespread activation, remarkable extrafollicular maturation and persistence, expansion and somatic diversification of self-reactive clones. Through the model of pRD, we reveal a RAG-dependent 'domino effect' that impacts stringency of tolerance and B cell fate in the periphery.

Implementation of TREC/KREC detection protocol for newborn SCID screening in Bulgaria: a pilot study.

Neonatal screening for inborn errors of immunity (IEI), based on quantification of T-cell-receptor- excision circles (TRECs) and kappa-deleting recombination-excision circles (KRECs) from dried blood spots (DBS), allows early diagnosis and improved outcomes for the affected children. Determination of TREC/KREC levels from prospectively collected newborns' Guthrie cards and from DBS samples of patients with confirmed IEI was done using a commercial kit. Retrospective assessment of flow cytometry evaluation of TREC/KREC correspondence with lymphocyte subpopulations and evaluation of the correlations between TREC and KREC with immune cells, based on the data from patients with suspected or confirmed immune disorders, were conducted. 2,228 Guthrie cards were tested, 1276 for TREC only and 952 for both TREC and KREC. Eight newborns (0.36%) were TREC positive and 10 (1.05%) had KREC below the cut-off. The re-testing rate was 1.88%. Retrospective analysis demonstrated that the TREC/KREC assay identifies 100% of severe combined immune deficiencies (SCID) cases when DBS were collected at birth. Correlation analysis showed moderate significant correlations between TREC and the absolute numbers of CD4 cells (r = 0.634, p < 0.01) and total T cells (r = 0.536, p < 0.01). The ability of KREC levels to predict abnormal absolute (AUC of 0.772) and relative (AUC 0.731) levels of B cells was demonstrated.

Immune Cell Subsets Evaluation as a Predictive Tool for Hepatitis B Infection Outcome and Treatment Responsiveness.

BACKGROUND: The patient's immune response is one of the major factors influencing HBV eradication or chronification, and it is thought to be responsible for the treatment success. AIM: Our study aimed to investigate whether cellular defense mechanisms are associated with the course of HBV infection (spontaneous recovery [SR] or chronification [CHB]) and with the therapeutic approach. PATIENTS AND METHODS: A total of 139 patients (118 with CHB, 21 SR) and 29 healthy individuals (HI) were immunophenotyped by flowcytometry. Fifty-six patients were treatment-naïve, 20 were treated with interferons and 42 with nucleoside/ nucleotide analogues. RESULTS: Deficiency of T lymphocytes, helper-inducer (CD3+CD4+), suppressorcytotoxic (CD8+CD3+) and cytotoxic (CD8+CD11b-, CD8+CD28+) subsets, activated T cells (CD3+HLA-DR+, CD8+CD38+) and increased CD57+CD8- cells, elevated percentages of B lymphocytes and NKT cells were observed in CHB patients compared with HI. In SR patients, elevated CD8+CD11b+, NKT and activated T cells were found in comparison with controls. The higher values of T cells and their subsets in SR patients than in CHB patients reflect a recovery of cellular immunity in resolved HBV infection individuals. In both groups of treated patients, reduced T lymphocytes, CD3+CD4+ and CD8+CD38+ subsets were found in comparison with HI. Higher proportions of cytotoxic subsets were observed in treated patients compared with treatment-naïve CHB patients, more pronounced in the group with interferon therapy. CONCLUSION: Our data demonstrate that cellular immune profiles may be of prognostic value in predicting the clinical course of HBV infection, and the determination of the therapeutic response.

NGS-based mtDNA Profiling Could Reveal Genetic Alterations in Schizophrenia.

BACKGROUND: Schizophrenia is a complex disease with a putative genetic background. It was hypothesized that impaired mitochondrial function due to genetic alterations in mitochondrial DNA (mtDNA) could contribute to neurological conditions, including mental disorders. The aim of the study was to find out possible pathogenic mutations and/or variants in mtDNA potentially related to schizophrenia development. OBJECTIVE: The study involved 37 patients with paranoid schizophrenia, whose mtDNA profiles were compared to those of 23 healthy controls. METHODS: Patients and controls were assessed using PANSS (Positive and Negative Syndrome Scale) and General Health Questionnaire (GHQ), respectively. The entire mtDNA was sequenced by the NGS platform (MiSeq®, Illumina). Bioinformatics data were processed by mtDNA Variant Processor and Analyser (Illumina), mtDNA-Server, and SPSS-17. RESULTS: A total of 480 mtDNA variants (single nucleotide replacements, point insertions, and deletions) were found. The polymorphic variant m.1811A>G (MT-RNR2) showed the highest frequency in schizophrenia (24.3%), as compared to the controls (4.3%) (p=0.07). Increased frequency was also found mainly in polymorphisms, belonging to complex 1 genes: MT-ND4 (11251G and 11467G), MT-ND3 (10398G), MT-ND1 (4216С), and MT-ND5 (12611G and 13708А), some of which were associated with mitochondrial dysfunction. Two individual mutations were identified in the patients: a pathogenic one - m.11778 A>G (LHON) and a newly identified, potentially pathogenic - m.4115 Т>C (NADH dehydrogenase 1). CONCLUSION: Particular mtDNA variants predominantly in complex I, probably serve as a risk genetic background in schizophrenia. The presence of pathogenic mutations in patients with psychotic manifestations expands the clinical scope of mitochondrial diseases and deserves further investigation.

On Two Cases with Autosomal Dominant Hyper IgE Syndrome: Importance of Immunological Parameters for Clinical Course and Follow-Up.

Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare disease described in 1966. It is characterized by severe dermatitis, a peculiar face, frequent infections, extremely high levels of serum IgE and eosinophilia, all resulting from a defect in the STAT3 gene. A variety of mutations in the SH2 and DNA-binding domain have been described, and several studies have searched for associations between the severity of the clinical symptoms, laboratory findings, and the type of genetic alteration. We present two children with AD-HIES-a girl with the most common STAT3 mutation (R382W) and a boy with a rare variant (G617E) in the same gene, previously reported in only one other patient. Herein, we discuss the clinical and immunological findings in our patients, focusing on their importance on disease course and management.

The Clinical and Genetic Spectrum of 82 Patients With RAG Deficiency Including a c.256_257delAA Founder Variant in Slavic Countries.

Background: Variants in recombination-activating genes (RAG) are common genetic causes of autosomal recessive forms of combined immunodeficiencies (CID) ranging from severe combined immunodeficiency (SCID), Omenn syndrome (OS), leaky SCID, and CID with granulomas and/or autoimmunity (CID-G/AI), and even milder presentation with antibody deficiency. Objective: We aim to estimate the incidence, clinical presentation, genetic variability, and treatment outcome with geographic distribution of patients with the RAG defects in populations inhabiting South, West, and East Slavic countries. Methods: Demographic, clinical, and laboratory data were collected from RAG-deficient patients of Slavic origin via chart review, retrospectively. Recombinase activity was determined in vitro by flow cytometry-based assay. Results: Based on the clinical and immunologic phenotype, our cohort of 82 patients from 68 families represented a wide spectrum of RAG deficiencies, including SCID (n = 20), OS (n = 37), and LS/CID (n = 25) phenotypes. Sixty-seven (81.7%) patients carried RAG1 and 15 patients (18.3%) carried RAG2 biallelic variants. We estimate that the minimal annual incidence of RAG deficiency in Slavic countries varies between 1 in 180,000 and 1 in 300,000 live births, and it may vary secondary to health care disparities in these regions. In our cohort, 70% (n = 47) of patients with RAG1 variants carried p.K86Vfs*33 (c.256_257delAA) allele, either in homozygous (n = 18, 27%) or in compound heterozygous (n = 29, 43%) form. The majority (77%) of patients with homozygous RAG1 p.K86Vfs*33 variant originated from Vistula watershed area in Central and Eastern Poland, and compound heterozygote cases were distributed among all Slavic countries except Bulgaria. Clinical and immunological presentation of homozygous RAG1 p.K86Vfs*33 cases was highly diverse (SCID, OS, and AS/CID) suggestive of strong influence of additional genetic and/or epigenetic factors in shaping the final phenotype. Conclusion: We propose that RAG1 p.K86Vfs*33 is a founder variant originating from the Vistula watershed region in Poland, which may explain a high proportion of homozygous cases from Central and Eastern Poland and the presence of the variant in all Slavs. Our studies in this cohort of RAG1 founder variants confirm that clinical and immunological phenotypes only partially depend on the underlying genetic defect. As access to HSCT is improving among RAG-deficient patients in Eastern Europe, we anticipate improvements in survival.

The Influence of HLA and KIR Genes on Malignant Melanoma Development and Progression.

Many studies have described the role of killer immunoglobulin-like receptors (KIRs) and their cognate human leukocyte antigen (HLA) class I ligands in the immune protection against melanoma, but the effect of these markers on intra-individual variations in tumor development and progression has remained less clear. We performed KIR, HLA, and KIR/ligand analysis in 283 patients with malignant melanoma in order to evaluate their integrated influence on disease stage and progression. The patients were grouped according to AJCC staging, histological type of the primary tumor, progression, and survival rate. Analysis of HLA class I alleles revealed positive association of HLA-C*14 (Pc = 0.026, OR = 5.99) and negative association of HLA-C*02 (Pc = 0.026, OR = 0.43) with the disease. Decreased frequency of KIR2DS5 was observed in patients with rapid progression, as compared to those with slow progression. KIR BB genotype was prevalent in patients with metastasis (p = 0.004, OR = 0.025). KIR AA genotype was nearly twice as frequent in rapidly progressive cases, but without statistical relevance (p = 0.055, OR = 2.6). Significantly increased frequency of KIR2DL2 in the presence of C1 ligand (strong inhibition) was found in patients with AJCC III and IV, as compared to individuals with AJCC I stage (p = 0.045, OR = 1.93). In summary, our data imply that KIR/ligand gene content in patients could modulate the disease course towards unfavorable tumor behavior.