Article Text
Abstract
Background In spite of the fact that chronic arthritis has been the core of paediatric rheumatology, etiology and pathogenesis of juvenile idiopathic arthritis (JIA) are still unclear. It is important to ascertain genetic nature of such a heterogeneous disease.
Objectives The aim of the study was to assess the role of some SNPs of six genes implicated in immune and inflammatory responses: TNFα (rs1800629, rs361525), PTPN22 (rs2476601), MIF (rs755622, rs5844572), TRAF/C5 (rs3761847), CTLA4 (rs5742909, rs231775), STAT4 (rs7574865); as well as homozygous deletions of xenobiotic biotransformation genes GSTT1 and GSTM1.
Methods 206 patients diagnosed with JIA (mean age 8.87±4.92), and 218 hospital controls with no signs of autoimmune or inflammatory diseases (mean age13.88±2.72) were recruited for the study. The JIA patients were divided into subgroups according to IIAR classification criteria; the majority of them (125 patients) had oligoarthritis, 42 children developed RF-negative polyarthritis and 27 patients were diagnosed with systemic arthritis. Genomic DNA was extracted from peripheral blood samples by means of the phenol-chloroform method. SNPs were genotyped using PCR-RFLP, Real-Time PCR or fragmental analysis.
Results The allele frequencies for all SNPs in the hospital control group were similar to those in European populations. The allele and genotype frequency distribution for all SNPs was identical in patients and controls. However, when comparing distinct subtypes of JIA, STAT4 polymorphism demonstrated higher frequencies of minor T allele (30.5% vs. 17.8%, p=0.01, OR=2.03, 95% CI [1.14–3.6] and G/T genotype (46.3% vs. 25.6%, p=0.03, OR=2.51, 95%[1.2–5.24]) in RF-negative polyarthritis than in oligoarthritis. On the contrary, ΔGSTT1 appeared to prevail in oligoarthritis (23.7% vs. 7.9% in RF-negative polyarthritis, p=0.03, OR=3.6, 95% CI [1.03–12.7]). As to systemic arthritis, it was shown, that minor G allele of TRAF/C5 was more frequent in comparison with oligoarthritis (p=0.037, OR=2.43, 95% CI [1.05–5.6]).
Conclusions The results obtained can be considered as evidence for distinct genetic nature of the different JIA subtypes.
Disclosure of Interest None declared