The tolerogenic peptide hCDR1 immunomodulates cytokine and regulatory molecule gene expression in blood mononuclear cells of primary Sjogren's syndrome patients

Primary Sjogren's syndrome (pSS) is an autoimmune disease characterized by lymphocytic infiltration of exocrine glands. We investigated whether the tolerogenic peptide, hCDR1, that ameliorates lupus manifestations would have beneficial effects on pSS as well. The in vitro effects of hCDR1 on gene expression of pro-inflammatory cytokines and regulatory molecules were tested in peripheral blood mononuclear cells (PBMC) of 16 pSS patients. hCDR1, but not a control peptide, significantly reduced gene expression of IL-1β, TNF-α, MX-1 and BlyS and up-regulated immunosuppressive (TGF-β, FOXP3) molecules in PBMC of pSS patients. hCDR1 did not affect gene expression in patients with rheumatoid arthritis and anti-phospholipid syndrome. Further, hCDR1 up-regulated the expression of Indoleamine 2,3-dioxygenase (IDO) via elevation of TGF-β. IDO inhibition led to a significant decrease in the expression of FOXP3 which is crucial for the induction of T regulatory cells. Thus, hCDR1 is potential candidate for the specific treatment of pSS patients.