Prolidase-deficient mice also demonstrate an activated T cell phenotype and elevated serum IgA, with glomerular immune complex deposition reminiscent of early human lupus nephritis (44), mimicking the phenotype in a subset of PD patients (7, 8, 11, 45) and confirming, to our knowledge, for the first time, the direct association of autoimmunity and PD. This evidence concerns the gene PEPD and Autoimmunity.