Expression of CD81, SR-BI and LDLR in lymphocytes and monocytes from patients with classic and occult hepatitis C virus infection.

CD81, the scavenger receptor-BI (SR-BI) and the low-density lipoprotein receptor (LDLR) are involved in peripheral blood mononuclear cells (PBMCs) hepatitis C virus (HCV) entry. To investigate if these molecules are altered by HCV, 20 controls and 66 patients: 37 untreated and 29 sustained virological responders, were studied. CD81 and LDLR expression, measured the percentage of cells expressing the HCV-receptors and their mean fluorescence intensity (MFI), was analyzed on lymphocytes and monocytes, as well as SR-BI on monocytes by flow cytometry. RNA was extracted from PBMCs and detection of the HCV-RNA positive and negative strands was performed by strand-specific RT-PCR. A statistically significant increase of CD81 expression was observed on lymphocytes, a higher percentage of LDLR on lymphocytes and monocytes, as well as SR-BI on monocytes was found in the patients as compared to the controls (P < 0.05 in all cases). Untreated patients showed a higher percentage of LDLR(+) lymphocytes than sustained virological responders (P = 0.025). Nineteen sustained virological responders bore the HCV-RNA positive strand in PBMCs; nine of them the negative strand too. Sustained virological responders with occult infection and viral replication, showed a higher expression of LDLR on lymphocytes (P < 0.05) and a higher LDLR MFI on monocytes (P = 0.011) than those without viral replication. In conclusion, HCV exposure modifies expression levels of the receptors studied, being LDLR related with HCV replication, not only in the classic but also in the occult infection.