T-CELL RECEPTOR BV6S1 NULL ALLELES AND HLA-DR1 HAPLOTYPES IN POLYARTICULAR OUTCOME JUVENILE RHEUMATOID-ARTHRITIS

JRA is a complex of disease subtypes which are normally identified by clinical features such as age of onset and extent of joint involvement both at onset and during the course of the disease. We previously ide ntified an association between TCR BV6S1 null allele and one subgroup of early-onset pauciarticular patients positive for HLA-DQA10101, an HLA haplotype predisposing to a polyarticular course of the disease. I n this report we extend this observation by identifying an increased p revalence of this nonfunctional or null allele in the patients with a polyarticular disease course regardless of the mode of onset. This inc rease was most prominent in clinical subsets that have early onset of the disease and a polyarticular outcome. In one clinical group, strati fication of patients by the HLA allele DQA10101 strengthened the asso ciation considerably. This implies that there is an increased genetic load defined by specific alleles of both MHC and TCR genes.