IMMUNE-RESPONSES TO THE ESCHERICHIA-COLI DNAJ HEAT-SHOCK PROTEIN IN JUVENILE RHEUMATOID-ARTHRITIS AND THEIR CORRELATION WITH DISEASE-ACTIVITY

Patients with juvenile rheumatoid arthritis frequently have abnormal i mmune responses to the hsp65 class of bacterial heat shock proteins. H owever, lymphocytes from children with other inflammatory diseases may also recognize hsp65, and the role of these antigens in juvenile rheu matoid arthritis remains controversial. We have studied humoral and ce llular immune responses to a distinct, recently described bacterial he at shock protein, designated dnaJ. The Escherichia coli dnaJ gene was cloned and expressed, and the purified recombinant protein was used as an antigen. Neither normal children nor children with various chronic inflammatory diseases had lymphocyte proliferative responses to recom binant dnaJ. However, lymphocytes from patients with polyarticular, pa uciarticular, and systemic manifestations of juvenile rheumatoid arthr itis responded strongly to the antigen. Cellular immune responses to d naJ were higher in synovial fluid than in blood and higher in children with active disease than in children in remission. These data show th at increased immune reactivity to dnaJ is characteristic of juvenile r heumatoid arthritis and that the magnitude of the immune response is l inked to disease activity. The results suggest that an abnormal immune response to antigens on commensal gut bacteria may contribute to the generation of chronic inflammation in juvenile rheumatoid arthritis.