Although CD4 and CD8 effector T cells with an inflammatory phenotype were expanded in the WT:Pepd−/− chimeric mice, the proportion of SLEC-like effector cells and serum IgA and ANA production were normal, highlighting a potential relationship between disease activity of SLEC-like effectors and hallmarks of autoimmunity in the absence of prolidase. Here, CD4 is linked to Autoimmunity.