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^high/57⁺/27^-/45RA⁺, less cytotoxic CD8^high/57^-/27^-/45RA⁺ effector cells and cytotoxic memory CD8^high/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.

Activity of T-helper cells in patients with primary Sjogren's syndrome

AIM

To investigate the T-helper (Th1, Th2 and Th17) cell activity in the peripheral blood of patients with primary Sjögren's syndrome (pSS), non-Sjögren's sicca syndrome (nSS) and healthy controls.

PATIENTS AND METHODS

Peripheral blood mononuclear cells from 34 pSS, 13 nSS patients and 13 healthy controls were stimulated, labeled for cluster of differentiation-4 (CD4), interferon-γ (IFN-γ), interleukin-4 (IL-4) and IL-17A and analyzed by flow cytometry.

RESULTS

The activities of Th1 and Th17 cells in patients with pSS were similar to those of the control group. The percentage of both IFN-γ- and IL-17-producing Th17/Th1-like cells was significantly higher in the pSS, as compared to the control group, whereas that of Th2 cells was lower. A significant correlation was found between all Th-subset activities in the control group. However, in the pSS group, a correlation was found only between Th1 with Th2 and Th17 and Th17 with Th17/Th1-like.

CONCLUSION

The imbalance in Th-subset activities in peripheral blood may play a role in the pathogenesis of pSS.