Such an inhibitory effect of CD25+ Treg on autoantigen-specific CD4+ T cell responses and their unmasking by in vitro depletion of CD25+ Treg before antigen stimulation was also reported for the detection of SmD1p-specific CD4+ T cells in human SLE patients thereby enabling their correlation with disease activity (18). The gene discussed is CD4; the disease is systemic lupus erythematosus.