RHEUMATOID-ARTHRITIS IN TLINGIT INDIANS - CLINICAL CHARACTERIZATION AND HLA ASSOCIATIONS

Objective. To characterize the features of rheumatoid arthritis (RA) i n Tlingit Indians, to identify the HLA-DR alleles associated with RA i n the Tlingit, and to determine whether disease severity or specific c linical manifestations correlate with the presence of specific HLA ant igens. Method. Thirty-seven Tlingit patients with RA and 75 controls w ere evaluated clinically; comparative HLA studies were carried out in 33 patients and 62 controls. Results. The results of this clinical stu dy of RA in the Tlingit confirms that the disease found in them is cla ssical RA, characterized by an early age of onset, a high frequency of nodules, serum rheumatoid factor (RF) and antinuclear antibodies (ANA ); an often severe clinical course, with a high frequency of erosive d isease and frequent need for surgical joint repair, and an often posit ive family history. In Tlingit volunteers who did not have RA we also found an increased prevalence of RF and ANA. Neither HLA-DR1 nor DR4 w as found to be associated with RA in the Tlingit. The commonest DR ant igen in patients with RA was DR14. The most frequent DRB1 allele was D RB11402 (Dw16). Conclusion. The Tlingit population had a very high fr equency of the DRB11402 allele, which shares key sequence homology wi th DRB10401 (Dw4) and DRB1*0101 (Dwl), associated with RA in other ra cial groups. No correlations were found between specific HLA-DRB1 alle les or combinations of alleles and specific disease features or severi ty.