Several associations between HLA polymorphisms and JIA subtypes have been reported in multiple populations, but with significant variations across different ethnic groups. The aim of our study was to search specific HLA-DRB1, -DQA1 and -DQB1 polymorphisms that are associated with JIA and different disease phenotypes in Romanian patients compared with other ethnic groups.
HLA genotyping was performed in 61 JIA patients and 30 ethnicity-matched controls using molecular biology methods, PCR-SSOP.
A protective effect across the whole cohort was observed for HLA-DRB1*15 (OR = 0.179, 95% CI: 0.054 -0.58) and HLA-DQB1*06 (OR = 0.285, 95% CI: 0.11-0.72). Each ILAR subgroup had a characteristic pattern of HLA associations. Unlike other populations, we found a positive association of HLA-DQA1*03 with chronic uveitis (OR = 14.67, 95% CI: 1.5-143) and a negative association of HLA-DQA1*01 with early disease onset (OR = 0.175, 95% CI: 0.036- 0.862), suggesting that the HLA-DR/DQ profile can affect the clinical expression of the disease.
The study reveals multiple HLA-DR/DQ associations with JIA, not only similar with those found in other populations, but also some distinctive associations. However, some of the previously established associations were not replicated in Romanian patients. These results might be due to the small size of our cohort or to true population differences.