DNAJB1 and juvenile idiopathic arthritis: In order to study T- cell responses to HSP40 peptide fragments in patients with oligoarticular juvenile arthritis, Massa et al. [48] showed that proliferative responses of patient synovial fluid monocytes (SFMCs) to recombinant E. coli HSP40 (rdnaJ) were significantly higher than those of the corresponding peripheral blood monocytes.