Relevancia de TLR4 en la infección por virus de la hepatitis C

Objective

The presence of the Asp-299Gly and Thr-399Ile polymorphisms in the toll-like receptor 4 (TLR4) gene was studied in subjects with HCV infection and HCV+HIV coinfection. The expression and function of TLR4 as regards these polymorphisms is assessed.

Material and methods

The study included 53 patients infected with HCV, among whom 27 had coinfection HCV+HIV, and 30 healthy subjects. The polymorphisms were studied by PCR-RFLP. The number of lymphocyte subsets, as well as TLR4 expression, was determined by flow cytometry, and the concentration of cytokines was measured in serum by (cytometric bead assay) CBA.

Results

CD4⁺ T cells were significantly decreased in patients coinfected with HCV+HIV. There was no association between the presence of any of the two studied polymorphisms and the susceptibility to suffer from infection. TLR4 was less expressed in B cells, whereas it was increased in T cells and, in particular, monocytes. A significant increase in the levels of circulating pro-inflammatory cytokines was found, being two-fold increased in coinfected subjects as compared with patients with isolated HCV infection. None of the findings in cell subsets, TLR4 expression and cytokines was associated with the studied TLR4 polymorphism.

Discussion

The expression of TLR4 in T cells and monocytes is increased in HCV infection and is accompanied by increased serum levels of proinflammatory cytokines. These findings do not have any relationship with the Asp-299Gly and Thr-399Ile polymorphisms.