Anti-IL12A monoclonal antibody, clone 35056

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is an enduring public health problem globally, particularly in sub-Saharan Africa. Several studies have suggested a role for host genetic susceptibility in increased risk for TB but results across studies have been equivocal. As part of a household contact study of Mtb infection and disease in Kampala, Uganda, we have taken a unique approach to the study of genetic susceptibility to TB, by studying three phenotypes. First, we analyzed culture confirmed TB disease compared to latent Mtb infection (LTBI) or lack of Mtb infection. Second, we analyzed resistance to Mtb infection in the face of continuous exposure, defined by a persistently negative tuberculin skin test (PTST-); this outcome was contrasted to LTBI. Third, we analyzed an intermediate phenotype, tumor necrosis factor-alpha (TNF alpha) expression in response to soluble Mtb ligands enriched with molecules secreted from Mtb (culture filtrate). We conducted a full microsatellite genome scan, using genotypes generated by the Center for Medical Genetics at Marshfield. Multipoint model-free linkage analysis was conducted using an extension of the Haseman-Elston regression model that includes half sibling pairs, and HIV status was included as a covariate in the model. The analysis included 803 individuals from 193 pedigrees, comprising 258 full sibling pairs and 175 half sibling pairs. Suggestive linkage (p, 10 23) was observed on chromosomes 2q21-2q24 and 5p13-5q22 for PTST-, and on chromosome 7p22-7p21 for TB; these findings for PTST-are novel and the chromosome 7 region contains the IL6 gene. In addition, we replicated recent linkage findings on chromosome 20q13 for TB (p = 0.002). We also observed linkage at the nominal a = 0.05 threshold to a number of promising candidate genes, SLC11A1 (PTST-p = 0.02), IL-1 complex (TB p = 0.01), IL12BR2 (TNF alpha p = 0.006), IL12A (TB p = 0.02) and IFNGR2 (TNF alpha p = 0.002). These results confirm not only that genetic factors influence the interaction between humans and Mtb but more importantly that they differ according to the outcome of that interaction: exposure but no infection, infection without progression to disease, or progression of infection to disease. Many of the genetic factors for each of these stages are part of the innate immune system.

Background. Kaposi sarcoma (KS) is primarily caused by human herpesvirus (HHV)-8 infection, and the risk is increased with high HHV-8 lytic or latent antibody titers or the detection of HHV-8 DNA in peripheral blood mononuclear cells (PBMCs). Host genes important for control of HHV-8 infection are not well characterized. Methods. In 172 HHV-8 latent nuclear antigen ( LANA)-seropositive adults in Italy without KS, we examined correlations of common variants in host immune genes with the detection of HHV-8 DNA in PBMCs and with high lytic and latent antibody titers. Twenty-eight single-nucleotide polymorphisms in 14 genes were analyzed. We detected HHV-8 DNA in PBMCs with real-time amplification of the K6 gene, anti-K8.1 ( lytic) titers with enzyme-linked immunosorbent assay, and anti-LANA ( latent) titers with immunofluorescence. Results. Detection of HHV-8 DNA in PBMCs was not significantly related to any variant examined. In contrast, a 3-locus haplotype of IL4, which contains the -1098G allele ( rs2243248), was overrepresented among subjects with high lytic titers ( odds ratio [ OR], 2.8 [ 95% confidence interval {CI}, 1.1-6.7]), compared with those with low titers, as was the functional promoter variant of IL6, C-236C ( rs1800795) ( OR, 3.7 [ 95% CI, 1.1-12.8]). Compared with subjects with low HHV-8 latent antibody titers, analysis of inferred haplotypes for IL12A revealed an overrepresentation of -798T/277A in subjects with high HHV-8 latent antibody titers ( OR, 2.4 [ 95% CI, 1.1-5.2]). Conclusions. Our observations are the first to provide preliminary evidence suggesting that common variants in key host immune genes could influence the control of HHV-8 infection.