engleski

Cholestasis-related expansion of perforin-expressing CD4+T lymphocytes in peripheral blood of patients with gallstones

The expression of perforin and granzymes is usually restricted to circulating CD8+ T cells and NK cells, while the ability of CD4+ T cells to display cytotoxic potential has been reported only in isolated reports in both mouse and human. Generally, the appearance of such cells was associated with chronic inflammatory conditions, viral infection and autoimmune diseases, but their functions in humans are still obscure. Owing to our previous findings that experimental biliary obstruction induces a significant immune dysfunction, followed by increased cytotoxic activities of hepatic and splenic mononuclear lymphatic cells (MNLC) against NK sensitive and syngeneic targets, in this study we analyzed the phenotypic characteristics of peripheral blood MNLC in 44 patients with gallstones and in 20 healthy donors. The subsets of lymphocytes were then in each person correlated with serum levels of bilirubin (B), alkaline phosphatase (AP), aspartat (AST) and alanine (ALT) aminotransferase, gamma-glutamyl transferase (GGT), C-reactive protein (CRP), glucose (G), urea (U) and creatinin (CR). METHODS: Flow cytometry was used for simultaneous detection of intracellular (perforin) and cell surface antigens on CD4+, CD8+, CD16+ and CD56+ cells. Serum constituents were analyzed by standard methods and linear regression equations were generated using a least-squares method and analyzed for differences of covariance. RESULTS: In patients with gallstones highly positive correlations were found between the serum levels of AP and ALT and percentage of CD4+P+ T cells (r=0.45 ; p<0.007 and r=0.46 ; p<0.006, respectively). Furthermore, high correlation was found between the serum levels of CRP and CD4+P+ cells (r=0.62 ; p<0000), suggesting that during cholestasis and chronic inflammatory conditions, increasing numbers of CD4+ T cells may undergo progressive differentiation, during which they gain expression of intracellular cytotoxic granules and perforin. According to current hypothesis, on such a way the cytotoxic CD4+ T cells probably down-regulate an immune response, acting as direct effectors of hepatocellular death, or as cells, which engaging the other cytotoxic cells, contribute, to the lyses of other activated APC. CONCLUSIONS: Taken together, the data show that expansion of cytotoxic CD4+P+ cells in peripheral blood in humans correlates with the intensity of cholestasis and liver damage, suggesting that CD4+P+ T lymphocytes might be cytotoxic, autoreactive cells which may have both protective and auto-aggressive potential.

Perforin; T lymphocytes; Peripheral blood; Gallstones

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