Dysregulation of toll-like receptor (TLR) 2 expression on monocytes and upregulation of the frequency of Tcells expressing TLR2 in patients with chronic hepatitis C virus infection

Toll-like receptors (TLRs) initiate inflammatory responses that may play a role in disease progression in patients infected with hepatitis C virus (HCV). TLR2 and TLR4 surface expression were assessed on CD14+ monocytes, CD4+ and CD8+ T cells in treatment naive patients with chronic HCV infection with fibrosis, without fibrosis, co-infected with human immunodeficiency virus (HIV), and in healthy controls. Increased expression of TLR2 was found on monocytes in HCV-infected patients with fibrosis (p<0.01), co-infected with HIV (p=0.03), and possibly in patients without fibrosis (p=0.07) when compared to controls. TLR2 positive CD4+ and CD8+ T cells were upregulated in patients with fibrosis only (p<0.01). However, expression of TLR2 was not associated with T cell activation. TLR4 expression was similar in patients and healthy controls. In conclusion, TLR2 expression on monocytes and the frequency of T cells expressing TLR2 may contribute to disease progression in chronic HCV infection.