Association of IL17 and IL23R gene polymorphisms with rheumatic heart disease in South Indian population.

BACKGROUND: IL-23/Th17 signaling pathway plays a crucial role in the cell-mediated immune response against bacterial infections and also in the pathogenesis of inflammatory and autoimmune diseases. Recent studies indicate that Th17 cell-associated cytokines are involved in the progression and maintenance of valvular lesions in rheumatic heart disease (RHD). Variants in the genes of cytokines that are potentially involved in Th17 response may influence interindividual differences in their expression levels, thereby contributing to the pathogenesis of immune-mediated diseases such as RHD. OBJECTIVE: The aim of the study is to investigate the association of IL17A, IL17F, and IL23R gene variants with the risk perception of RHD. METHODS: A total of 225 individuals (99 RHD patients and 126 healthy siblings) were recruited for the study. The IL17A (rs2275913), IL17F (rs763780), and IL23R (rs10889677) polymorphisms were determined by polymerase chain reaction restriction fragment length polymorphisms and amplification-refractory mutation system-polymerase chain reaction methods, respectively. RESULTS: The frequency of IL17A (rs2275913) A/A genotype was significantly high in pooled RHD patients (odds ratio [OR] = 2.76; pc = 0.021), rheumatic fever (RF) patients (OR = 14.5; pc = 0.0001), and mitral valvular lesions patients (OR = 2.74; pc = 0.039) when compared to healthy siblings. However, the IL17F (rs763780) and IL23R (rs10889677) polymorphisms did not show any association with RHD. CONCLUSIONS: The results suggest that IL17A (rs2275913) polymorphism is associated with the development of RF/RHD in South Indian population. Further studies are required to substantiate the association of these genes with the disease risk.

"HLA-G 3'UTR gene polymorphisms and rheumatic heart disease: a familial study among South Indian population".

BACKGROUND: Rheumatic heart disease (RHD) is an autoimmune disease where cross reactive CD4+ T cells are involved in the pathogenesis of valvular damage. Human Leukocyte Antigen-G (HLA-G), an immunosuppressive molecule playing a crucial role in the inhibition of T cell response is associated with the pathogenesis of various autoimmune and inflammatory diseases. Genetic polymorphisms within the 3'untranslated region (UTR) of HLA-G influences its expression and thus disease pathogenesis. Hence, the present study aims to unravel the association of 14 bp Ins/Del (rs66554220) and +3142 C/G (rs1063320) polymorphisms in 3' UTR of HLA-G with RHD. METHODS: This familial study consists of 99 RHD families (99 RHD patients, 140 parents and 126 healthy siblings). The 14 bp Ins/Del and +3142 C/G polymorphisms were evaluated by PCR using sequence specific primers and its transmission disequilibrium (TD) was tested by TD test in 70 trio families. RESULTS: The frequency of +3142 C/C genotype was high in patients with combined valvular lesions (CVL) (OR = 5.88; pc = 0.012) and pooled RHD patients (P: OR = 2.76; p = 0.043; pc = 0.076) when compared to healthy siblings. Under the additive (OR = 5.50; pc = 0.026) and recessive genetic model (OR = 5.88; pc = 0.012), the +3142 C/C genotype was significantly associated with CVL in patients. CONCLUSION: The results suggest that the +3142 C/C genotype may be associated with minor risk for the development of RHD and is more likely to influence the severity of the disease.