Juvenile idiopathic arthritis (JIA) is a complex immune-mediated disease characterized by environmental influences along with several predisposing genes in the pathogenesis. The present study was undertaken to investigate the association of polymorphisms in two candidate genes for autoimmunity, human leukocyte antigen (HLA) DRB1 and protein tyrosine phosphatase N22 (PTPN22) with JIA in Hungarian patients.
A case-control study including 150 Hungarian JIA patients and 200 sex and ethnically matched healthy controls was conducted. Genotyping for HLA-DRB1 and PTPN22 C1858T single nucleotide polymorphism (SNP) (rs2476601) was carried out by group-specific PCR amplification and by real-time PCR allelic discrimination, respectively.
In Hungarian patients JIA was associated with HLA-DRB1*01, DRB1*08, DRB1*13 (p=0.048, p=0.002, p=0.019, respectively) with marked differences between the disease subtypes classified according to the ILAR criteria. There was no association of the PTPN22 C1858T SNP with JIA (p=0.66). No correlation was found between the presence of this PTPN22 SNP and HLA-DRB1 alleles.
Our results confirm that certain HLA-DRB1 alleles reported previously as susceptibility factors are strongly associated with JIA in a Hungarian population. However, C1858T polymorphism of PTPN22, another candidate gene of autoimmunity seems to be independent of JIA in Hungarian patients. Our data taken together with various findings in different populations suggest that associations related to PTPN22 seem to be more ethnicity-specific in contrast to the general and less population-dependent role of HLA-DRB1 in JIA.