CD4 and dermatomyositis: In studies of the TCR-mediated intracellular signalling pathway, expression of signal transducer and activator of transcription (STAT), forkhead box transcription factor (FoxP3) and TCR-induced phosphorylated zeta-chain-associated protein kinase 70 (pZAP70) in CD4+ T cells of DM patients was found to be suppressed.