Introduction: Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease of unknown etiology. Killer cell immunoglobulin-like receptors (KIR) expressed on surface of natural killer cells and CD28 null T-cells which are present in synovial membrane of RA. The present study has evaluated associations of KIR genes with RA among North Indian population from Uttar Pradesh.
Materials and methods: KIR genotypes were determined in 100 RA cases and 100 healthy controls using sequence specific primer polymerase chain reaction (PCR-SSP) method.
Results: RA cases positive for KIR3DS1 (OR = 1.17, p-value = 0.0498) and KIR2DS2 (OR = 2.21, p-value = 0.0120) showed risk associations. While, KIR2DL2 (OR = 0.40, p-value = 0.0026), KIR2DL3 (OR = 0.44, p-value = 0.0283) and KIR3DL1 (OR=0.32, p-value = 0.0012) showed protective associations. Increased incidence of BB genotype (45%) was revealed among cases. Risk association was noted against telomeric region (OR = 2.12, p = 0.0120) genes for RA. Pair-wise linkage disequilibrium (LD) analysis among RA cases revealed KIR2DS1-2DL1 (D' = 0.83, r(2) = 0.36), KIR3DL1-3DS1 (D' = 1, r(2) = 0.58) and KIR2DL1-2DL2 (D' = 1, r(2)=0.61) to be in significant LD. KIR3DS1 and KIR2DS3 genes showed significant risk associations among RA patients with extra-articular manifestations (OR = 5.14, p-value = 0.0018; OR = 3.79, p-value = 0.0106) and in limited range of motion in affected joints (OR = 14.91, p-value = 0.0001; OR = 2.95, p-value=0.0126).
Conclusion: The KIR activating genes have risk association with RA in the present study.
Keywords: Autoimmune disease; Genetic association; Killer immunoglobulin like receptor (KIR); Polymerase chain reaction-sequence specific primer (PCR-SSP); Rheumatoid arthritis (RA).
Copyright © 2014. Published by Elsevier Inc.