Search

BackgroundMendelian susceptibility to mycobacterial disease (MSMD) is an inborn error of immunity, resulting in susceptibility to weakly virulent mycobacteria and other intramacrophagic pathogens. Rheumatologic manifestations and vasculitis are considered rare manifestations in MSMD patients.Case presentationIn this study, we reported a 20-year-old female who was presented with recurrent lymphadenitis following bacillus Calmette-Guérin (BCG) vaccination and a history of recurrent disseminated rash diagnosed as leukocytoclastic vasculitis (LCV). A slight reduction in lymphocyte subsets including CD4+, CD19+, and CD 16 + 56 T-cell count, as well as an elevation in immunoglobulins level (IgG, IgA, IgM, IgE), were observed in the patient. Whole exome sequencing revealed a homozygous Indel-frameshift mutation, c.527_528delCT (p. S176Cfs*12), at the exon 5 of theIL12Bgene. She experienced symptom resolution after treatment with anti-mycobacterial agents and subcutaneous IFN-γ. We conducted a manual literature search for MSMD patients reported with vasculitis in PubMed, Web of Science, and Scopus databases. A total of 18 MSMD patients were found to be affected by a variety of vasculitis phenotypes mainly including LCV and Henoch-Schönlein purpura (HSP) with often skin involvement. Patients were all involved with vasculitis at the median age of 6.8 (2.6–7.7) years, nearly 6.1 years after the initial presentations. Sixteen patients (88.9%) hadIL12RB1defects and concurrentSalmonellainfection was reported in 15 (88.2%) patients.ConclusionThe lack of IL-12 and IL-23 signaling/activity/function and salmonella infection may be triggering factors for the development of leukocytoclastic vasculitis. IL12B or IL12RB1 deficiency and salmonellosis should be considered in MSMD patients with vasculitis.

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare primary immunodeficiency, triggered by non-tuberculous mycobacteria or Bacillus Calmette-Guerin (BCG) vaccines and characterized by severe diseases. All known genetic etiologies are inborn errors of IFN-γ-mediated immunity. Here, we report the molecular, cellular, and clinical features of patients from 15 Iranian families with disseminated disease without vaccination (2 patients) or following live BCG vaccination (14 patients). We used whole blood samples from 16 patients and 12 age-matched healthy controls. To measure IL-12 and IFN-γ, samples were activated by BCG plus recombinant human IFN-γ or recombinant human IL-12. Immunological assessments and genetic analysis were also done for the patients. Eight patients affected as a result of parental first-cousin marriages. Seven patients originated from multiplex kindred with positive history of death because of tuberculosis or finding the MSMD-related gene mutations. Two patients died due to mycobacterial disease at the ages of 8 months and 3.7 years. The remaining patients were alive at the last follow-up and were aged between 2 and 13 years. Patients suffered from infections including chronic mucocutaneous candidiasis (n = 10), salmonellosis (n = 2), and Leishmania (responsible for visceral form) (n = 2). Thirteen patients presented with autosomal recessive (AR) IL-12Rβ1 deficiency, meaning their cells produced low levels of IFN-γ. Bi-allelic IL12RB1 mutations were detected in nine of patients. Three patients with AR IL-12p40 deficiency (bi-allelic IL12B mutations) produced low levels of both IL-12 and IFN-γ. Overall, we found five mutations in the IL12RB1 gene and three mutations in the IL12B gene. Except one mutation in exon 5 (c.510C>A) of IL12B, all others were previously reported to be loss-of-function mutations. We found low levels of IFN-γ production and failure to respond to IL12 in 13 Iranian MSMD patients. Due to complicated clinical manifestations in affected children, early cellular and molecular diagnostics is crucial in susceptible patients.

PURPOSE: Inborn errors of IFN-γ immunity underlie Mendelian susceptibility to mycobacterial disease (MSMD). Autosomal recessive complete IL-12Rβ1 deficiency is the most frequent genetic etiology of MSMD. Only two of the 84 known mutations are copy number variations (CNVs), identified in two of the 213 IL-12Rβ1-deficient patients and two of the 164 kindreds reported. These two CNVs are large deletions found in the heterozygous or homozygous state. We searched for novel families with IL-12Rβ1 deficiency due to CNVs. METHODS: We studied six MSMD patients from five unrelated kindreds displaying adverse reactions to BCG vaccination. Three of the patients also presented systemic salmonellosis, two had mucocutaneous candidiasis, and one had disseminated histoplasmosis. We searched for CNVs and other variation by IL12RB1-targeted next-generation sequencing (NGS). RESULTS: We identified six new IL-12Rβ1-deficient patients with a complete loss of IL-12Rβ1 expression on PHA-activated T cells and/or EBV-transformed B cells. The cells of these patients did not respond to IL-12 and IL-23. Five different CNVs encompassing IL12RB1 (four deletions and one duplication) were identified in these patients by NGS coverage analysis, in either the homozygous state (n=1) or in trans (n=4) with a single nucleotide variation (n=3) or a small indel (n=1). Seven of the nine mutations are novel. Interestingly, four of the five CNVs were predicted to be driven by nearby Alu elements, as well as the two previously reported large deletions. The IL12RB1 locus is actually enriched in Alu elements (44.7%), when compared with the rest of the genome (10.5%). CONCLUSION: The IL12RB1 locus is Alu-enriched and therefore prone to rearrangements at various positions. CNVs should be considered in the genetic diagnosis of IL-12Rβ1 deficiency.

The goal of this study was to investigate the relationship between polymorphisms in interleukin (IL)-12, IL-12R, IL-23, and IL-23R genes and Takayasu arteritis (TA) in a Chinese population. A case–control study was performed to investigate the associations of 19 single nucleotide polymorphisms (SNPs) mapping to IL12A, IL12B, IL12RB1, IL12RB2 and IL23R with susceptibility to TA in 145 Chinese TA patients and 300 healthy controls. Genotype identification was performed with the MassARRAY system from Sequenom. The statistical analysis was conducted by Chi square test and unconditional logistic regression with plink. No significant differences were found for the distribution of allele and genotype frequencies of these SNPs between TA patients and healthy controls. However, a trend for IL12A rs582054 and IL23R rs1004819 in association with the TA phenotype was detected. TA patients carrying the rs582054/rs568408 haplotype (P′ = 0.019) appeared less likely to progress to a more severe form of disease. And the C allele (P′ = 0.082) of IL23R rs1004819 appeared to be a protective factor to refractory disease. These findings suggest that the polymorphisms of IL12A, IL12B, IL12RB1, IL12RB2 and IL23R might make no contribution to the susceptibility of TA in the Chinese population.

Mycobacterium avium ssp. paratuberculosis (MAP) infection causes a chronic granulomatous inflammatory condition of the bovine gut that is characterized by diarrhea, progressive weight loss, and emaciation, and ultimately leads to loss in productivity and profitability of dairy operations. The host cytokine machinery is known to play an important role in protecting against MAP infection. Therefore, the goal of the present study was to assess whether polymorphisms in candidate genes encoding important cytokines and cytokine receptors are associated with MAP infection status of dairy cattle. MAP infection status was evaluated based on serum and milk enzyme-linked immunosorbent assays (ELISAs) for MAP-specific antibodies. Twenty previously reported polymorphisms in genes encoding bovine interferon gamma (IFNG), IFNGR1, IFNGR2, IL22, IL22RA1, IL12RB1, IL12RB2, and IL23R were genotyped in a resource population of 446 dairy Holsteins with known MAP infection status, and logistic regression was used to assess the statistical association with a binomial MAP infection status phenotype. Four SNPs in IFNGR2, IL12RB1, IL12RB2, and IL23R were found to be associated with the MAP infection status of the resource population. These results underscore the importance of cytokines and their receptors in conferring protection against MAP infection and warrant further functional characterization of these associations.

IL-12/23-interferon-gamma circuit enhances reactive oxygen species (ROS) synthesis in macrophage to attack intracellular pathogens such as mycobacteria and salmonella. Defective ROS in patients with chronic granulomatous disease (CGD) have increased susceptibility to these pathogens. However, patients with defective IL-12/23-interferon-gamma circuit rather than CGD are not recognized in Taiwan, endemic for tuberculosis and salmonella.The purpose of this study was to identify Taiwanese patients with defective IL-12/23-IFN-gamma circuit.In a long-term molecular study of primary immunodeficiency diseases (PIDD), the tentative CGD patients presenting with Bacille Calmette-Guerin (BCG)-induced infection, refractory atypical mycobacterial cutaneous granuloma and osteomyelitis, recurrent salmonella sepsis, and pneumatocele were studied for the IL-12/23-IFN-gamma circuit. ROS was first measured to exclude CGD. Candidate genes of IL12RB1, IFNRG1, IL12p40, IFNRG2, signal transducer and activator of transcription-1, and NF-kappaB essential modulator and their encoding protein expressions were analyzed.Of the 175 Taiwanese PIDD patients during a 28-year period, three patients from two unrelated families were identified with the hotspot INFRG1 deletion mutation (818del4) and had CGD features, presenting as cutaneous granuloma, and multiple osteomyelitis infected by non-tuberculosis mycobacteria, Mycobacteria avium complex and Mycobacterium scrofulaceum. Another with mis-sense IL12RB1 mutation (Arg211Pro) was noted as recurrent Salmonella enteritidis D sepsis and pneumatocele.Patients with defective IL-12/23-IFN-gamma circuit may resemble or overlap CGD manifestations of refractory cutaneous atypical mycobacterial granuloma and salmonella pneumatocele.

Interleukin-12 receptor beta 1 ( IL12RB1), interleukin-12 receptor beta 2 ( IL12RB2), and interferon gamma receptor 1 ( IFNGR1) perform important roles in the host defense against intracellular pathogens such as Mycobacteria. Several mutations within their genes have been confirmed as associated with increased susceptibility to mycobacterial infection. However, the association between mutations of the IL12RB1, IL12RB2, and IFNGR1 encoding genes and lepromatous leprosy has not been studied. This study screened for polymorphisms within IL12RB1, IL12RB2, and IFNGR1 encoding genes in the Korean populations using polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) DNA sequencing assay, and an association study was performed using the missense mutations of 705 A/G (Q214R), 1196 G/C (G378R), 1637 G/A (A525T), and 1664 C/T (P534S) of the IL12RB1, 83 G/A (V14M), and 1443 T/C (L467P) for the IFNGR1 encoding genes. There were no differences in the genotype and allele frequencies of IL12RB1 and IFNGR1 genes between 93 lepromatous leprosy patients and 94 control subjects. In conclusion, missense mutations of 705 A/G (Q214R), 1196 G/C (G378R), 1637 G/A (A525T), 1664 C/T (P534S) of the IL12RB1, 83 G/A (V14 M), and 1443 T/C (L467P) of the IFNGR1 encoding genes have no association with the susceptibility to lepromatous leprosy in the Korean population.

The cytokine interleukin (IL)-12 is bound by a heterodimeric receptor and mediates a range of immunological activities, in particular, favouring the development of uncommitted T cells to the Th1 phenotype. Genes encoding elements of the IL-12 pathway are therefore good candidates for mediating susceptibility or resistance to a range of immune disorders, including Type I diabetes. We made a systematic search for variants in the human gene encoding the low-affinity IL-12 receptor, IL12RB1. Four single-nucleotide polymorphisms and two microsatellite polymorphisms were defined. We also tested these IL12RB1 alleles for involvement in Type I diabetes susceptibility, testing 131 families. Although suggestive evidence for linkage to a susceptibility gene was found, none of the IL12RB1 variants we defined demonstrated preferential transmission in these families.

Cell-mediated immunity (CMI) plays an essential role in human host defense against intracellular bacteria. Type-1 cytokines, particularly gamma interferon (IFN-gamma), interleukin-12 (IL-12), and IL-23, the major cytokines that regulate IFN-gamma production, are essential in CMI. This is illustrated by patients with unusual severe infections caused by poorly pathogenic mycobacteria and Salmonella species, in whom genetic deficiencies have been identified in several key genes in the type-1 cytokine pathway, including IL12RB1, the gene encoding the beta1 chain of the IL-12 and IL-23 receptors. Several mutations in IL12RB1 with deleterious effects on human IL-12R function have been identified, including nonsense and missense mutations. In addition, a number of coding IL12RB1 polymorphisms have been reported. In order to gain more insight into the effect that IL12RB1 mutations and genetic variations can have on IL-12Rbeta1 function, three approaches have been followed. First, we determined the degree of conservation at the variant amino acid positions in IL-12Rbeta1 between different species, using known deleterious mutations, known variations in IL-12Rbeta1, as well as novel coding variations that we have identified at position S74R and R156H. Second, we analyzed the potential impact of these amino acid variations on the three-dimensional structure of the IL-12Rbeta1 protein. Third, we analyzed the putative functions of different IL-12Rbeta1 domains, partly based on their homology with gp130, and analyzed the possible effects of the above amino acid variations on the function of these domains. Based on these analyses, we propose an integrated model of IL-12Rbeta1 structure and function. This significantly enhances our molecular understanding of the human IL-12 and IL-23 systems.

Host genetic factors may be important determinants of susceptibility to tuberculosis, and several candidate gene polymorphisms have been shown to date. A series of recent reports concerning rare human deficiencies in the type-1 cytokine pathway suggest that more subtle variants of relevant genes may also contribute to susceptibility to tuberculosis at the general population level. To investigate whether polymorphisms in the interleukin-12 receptor (IL-12R) gene predispose individuals to tuberculosis, we studied these genes by single-strand conformational polymorphism analysis and direct sequencing. Although no common polymorphisms could be identified in the IL-12R beta 2 gene ( IL-12RB2), we confirmed four single nucleotide polymorphisms (SNPs; 641A--G, 684C--T, 1094T--C, and 1132G--C) causing three missense variants (Q214R, M365T, G378R) and one synonymous substitution in the extracellular domain of the IL-12R beta 1 gene ( IL12RB1). All SNPs were in almost perfect linkage disequilibrium (D'=0.98), and two common haplotypes of IL12RB1(allele 1: Q214-M365-G378; allele 2: R214-T365-R378) were revealed. Polymerase chain reaction/restriction fragment length polymorphism and sequence analyses were used to type IL12RB1polymorphisms in 98 patients with tuberculosis and 197 healthy controls in Japanese populations. In our case-control association study of tuberculosis, the R214-T365-R378 allele (allele 2) was over-represented in patients with tuberculosis, and homozygosity for R214-T365-R378 (the 2/2 genotype) was significantly associated with tuberculosis (odds ratio: 2.45; 95% CI: 1.20-4.99; P=0.013). In healthy subjects, homozygotes for R214-T365-R378 had lower levels of IL-12-induced signaling, according to differences in cellular responses to IL-12 between two haplotypes. These data suggest that the R214-T365-R378 allele, i.e., variation in IL12RB1, contribute to tuberculosis susceptibility in the Japanese population. This genetic variation may predispose individuals to tuberculosis infection by diminishing receptor responsiveness to IL-12 and to IL-23, leading to partial dysfunction of interferon-gamma-mediated immunity.

Background Malarial anaemia is characterized by destruction of malaria infected red blood cells and suppression of erythropoiesis. Interleukin 12 (IL12) significantly boosts erythropoietic responses in murine models of malarial anaemia and decreased IL12 levels are associated with severe malarial anaemia (SMA) in children. Based on the biological relevance of IL12 in malaria anaemia, the relationship between genetic polymorphisms of IL12 and its receptors and SMA was examined. Methods Fifty-five tagging single nucleotide polymorphisms covering genes encoding two IL12 subunits, IL12A and IL12B, and its receptors, IL12RB1 and IL12RB2, were examined in a cohort of 913 children residing in Asembo Bay region of western Kenya. Results An increasing copy number of minor variant (C) in IL12A (rs2243140) was significantly associated with a decreased risk of SMA (P = 0.006; risk ratio, 0.52 for carrying one copy of allele C and 0.28 for two copies). Individuals possessing two copies of a rare variant (C) in IL12RB1 (rs429774) also appeared to be strongly protective against SMA (P = 0.00005; risk ratio, 0.18). In addition, children homozygous for another rare allele (T) in IL12A (rs22431348) were associated with reduced risk of severe anaemia (SA) (P = 0.004; risk ratio, 0.69) and of severe anaemia with any parasitaemia (SAP) (P = 0.004; risk ratio, 0.66). In contrast, AG genotype for another variant in IL12RB1 (rs383483) was associated with susceptibility to high-density parasitaemia (HDP) (P = 0.003; risk ratio, 1.21). Conclusions This study has shown strong associations between polymorphisms in the genes of IL12A and IL12RB1 and protection from SMA in Kenyan children, suggesting that human genetic variants of IL12 related genes may significantly contribute to the development of anaemia in malaria patients.

Ligand-gated ion channels, a major class of cell-surface proteins, have a pseudosymmetric structure with five highly homologous subunits arranged around a central ion pore. The correct assembly of each channel, whose subunit composition varies with cell type and stage of development, requires specific recognition between the subunits. Assembly of the pentameric form of the acetylcholine receptor from adult muscle (AChR; alpha 2 beta epsilon delta) proceeds by a stepwise pathway starting with the formation of the heterodimers, alpha epsilon and alpha delta. The heterodimers than associate with the beta subunit and with each other to form the complete receptor. We have now determined which parts of the subunits mediate the interactions during assembly of the adult form of the receptor from mouse muscle by using a chimaeric subunit in which the N-terminal and C-terminal extracellular domains are derived from the epsilon subunit with the remainder from the beta subunit. The epsilon and beta subunits were chosen because the epsilon subunit forms a heterodimer with the alpha subunit in the pathway for assembly of the receptor, whereas the beta subunit does not. The epsilon beta chimera can substitute for the epsilon but not the beta subunit in the oligomeric receptor, indicating that the alpha subunit specifically recognizes an extracellular domain of the epsilon subunit.

The Distribution of Receptors for Interleukin (IL)-3, IL-6 and IL-8 in the Developing Human Fetus

Human-mouse hybrid cells were examined by indirect immunofluorescence with Mab DH12, a monoclonal antibody that recognizes the beta subunit of the human fibronectin receptor. Cells that expressed the antigen at their surface were sorted by FACS and karyotyped. Immunoaffinity chromatography on Mab DH12 was used to confirm the presence of the human antigen. The chromosome assignment was strengthened by isozyme analysis of markers for chromosomes 9 and 10. The results are suggestive for a 10p mapping of this beta subunit of the fibronectin receptor. Since the gene coding for the beta subunit of the VLA proteins was previously assigned to the same chromosome, our result could provide further evidence for the relationship between the beta subunit of the human fibronectin receptor and the VLA protein family.