Are cytotoxic effector cells changes in peripheral blood of patients with Sjögren's syndrome related to persistent virus infection: Suggestions and conundrums.

Etiology of Sjögren's syndrome (SS) is still unknown, but there is strong evidence that certain pathogens of bacterial or viral origin can incite autoimmune response. The aim of this study was to quantitatively evaluate changes of the main cell populations (dendritic cells, natural killer, natural killer T and cytotoxic T lymphocytes) presumably participating in virus clearance in peripheral blood of patients with primary SS (pSS). In analyzing cytotoxic T lymphocytes (CTL) populations we observed alterations in the frequency of highly cytotoxic effector CD8/57/27/45RA, less cytotoxic CD8/57/27/45RA effector cells and cytotoxic memory CD8/57/27/45RA effector cells. We found a decrease of conventional dendritic cells (cDC) population in peripheral blood of pSS patients. It is possible that, a decrease of effector CTL and cDC, accompanied by increase of transitory phenotype memory CTL in peripheral blood of pSS patients may be associated with viral etiopathogenesis of Sjögren's syndrome.