Influence of HLA-DR2 on perforin-positive cells in pulmonary tuberculosis

Influence of Genetic Polymorphism Towards Pulmonary Tuberculosis Susceptibility

Tuberculosis (TB) is still remains the major threat for human health worldwide. Several case-control, candidate-gene, family studies and genome-wide association studies (GWAS) suggested the association of host genetic factors to TB susceptibility or resistance in various ethnic populations. Moreover, these factors modulate the host immune responses to tuberculosis. Studies have reported genetic markers to predict TB development in human leukocyte antigen (HLA) and non-HLA genes like killer immunoglobulin-like receptor (KIR), toll-like receptors (TLRs), cytokine/chemokines and their receptors, vitamin D receptor (VDR) and SLC11A1 etc. Highly polymorphic HLA loci may influence antigen presentation specificities by modifying peptide binding motifs. The recent meta-analysis studies revealed the association of several HLA alleles in particular class II HLA-DRB1 with TB susceptibility and valuable marker for disease development especially in Asian populations. Case-control studies have found the association of HLA-DR2 in some populations, but not in other populations, this could be due to an ethnic specific association of gene variants. Recently, GWAS conducted in case-control and family based studies in Russia, Chinese Han, Morocco, Uganda and Tanzania revealed the association of genes such as ASAP1, Alkylglycerol monooxygenase (AGMO), Forkhead BoxP1 (FOXP1), C-terminal domain phosphatase 1 (UBLCP1) and intergenic SNP rs932347C/T with TB. Whereas, SNP rs10956514A/G were not associated with TB in western Chinese Han and Tibetan population. In this review, we summarize the recent findings of genetic variants with susceptibility/resistance to TB.

Single nucleotide polymorphic macrophage cytokine regulation by Mycobacterium tuberculosis and drug treatment

Aim: To investigate the survival of Mycobacterium tuberculosis in primary macrophages with SNPs affecting cytokine secretion under treatment with drugs in solution or microparticles. Materials & methods: Volunteers were typed for TNF (-308G/A), IL-10 (-1082A/G) and IL-4 (-590C/T). Monocyte-derived macrophages (MDMs) were infected in vitro. Cytokine secretion and survival of intracellular bacilli were estimated. Results: IL-10 AG associated with high secretion in uninfected and infected MDMs (p < 0.05) and was reduced more effectively by microparticles than drugs, irrespective of genotype (p < 0.05). Differences were observed between IL-4 secretion by MDMs of CC and TT genotypes (p = 0.1). Bacteria proliferated more in MDMs from volunteers with higher IL-4 levels (p = 0.05). Microparticles showed higher efficacy (p = 0.05) than drugs. Conclusion: IL-4 and IL-10 SNPs affect the ability of macrophages to counter infection with M. tuberculosis. Microparticles elicit favorable macrophage cytokines regardless of SNPs.

Original submitted 5 August 2013; Revision submitted 27 November 2013