Protective role of HLA-DRB۱*۱۱ against juvenile idiopathic arthritis living in North Eastern Iran

Objective(s): Juvenile idiopathic arthritis (JIA) is one of the most common chronic rheumatic diseases in children. The complex nature of this immune-mediated disease owes itself to several predisposing genes and environmental factors affecting its pathogenesis. Conducted in Iran, this study was originally intended to investigate every possible association between HLA DRB۱ alleles and a susceptibility to JIA.Materials and Methods: In this case-control study, ۴۵ patients with a definite diagnosis of JIA based on International League against Rheumatism (ILAR) criteria were compared against ۴۶ healthy controls. DNA samples taken from both groups were analyzed using PCR-sequence specific primers (PCR-SSP) method. Data analysis including parametric and nonparametric test and multivariate analysis was undertaken using the SPSS ۱۱.۵ software. A P-value< ۰.۰۵ was regarded as statistically significant.Results: Mean ages in case  group and healthy controls were ۱۴.۶۴±۶.۲۱ and ۱۳.۷۳±۶.۳۹, respectively with no significant difference between the two groups (P=۰.۵۱۵). Sex difference between JIA group and healthy controls was also not significant (P=۰.۰۶۸) .The frequency of HLA-DRB۱*۰۱ was found the most frequent HLA-RB۱ in our patients (۳۳.۳%). No significant statistical correlation between various HLA-DRB۱ alleles and clinical subtypes of the disease could be established from the data. HLA-DRB۱*۱۱ was shown to raise protection to JIA (P=۰.۰۳۵, OR=۲.۷۵۵, ۹۵% CI=۰.۹۶۳-۸.۰۵۵) in northeastern Iran. In addition, we found that HLA-RB۱*۰۹ is nominally associated with an increased risk of JIA (P=۰.۵۶, OR=۲, ۰۵, ۹۵% CI=۰.۱۸-۲۳.۶۳).Conclusion: HLA-DRB۱*۱۱ was shown to raise protection to JIA in northeastern Iran. The disparity of findings in other ethnicities prompts further investigations with larger sample sizes.

Keywords:

Allele frequency , HLA-DRB۱ , HLA typing , JIA , PCR-SSP