Platelets as a Possible Reservoir of HCV And Predictor of Response to Treatment
In the era of new Hepatitis C Virus (HCV) therapy, and the detection of extrahepatic HCV reservoirs such as peripheral blood mononuclear cells and platelets, it is important to understand the factors underlying resistance to treatment. Detection and quantitation of HCV-RNA in platelets or leucocytes from patients under antiviral therapy is poorly studied and the limited studies generated contradictory results.
Aim: To detect and quantify HCV-RNA in platelets, and to evaluate the relation between HCV-RNA in the serum and the kinetics of HCV-RNA in platelets, in response to treatment. Method: Viral kinetic was tested in 20 chronic HCV genotype4, during the course of therapy.
Results: HCV-RNA was detected in sera of all infected patients. The baseline platelet viral load was significantly lower in responders compared to non-responders. Platelet viral load was also related to serum viral load (t=3.39, p=0.001), but not related to platelet count (t=-0.56, p=0.58). ROC curve analysis revealed that in general, platelet viral load at different time points was a better predictor of SVR compared to serum viral load.
Conclusion: HCV RNA analysis in whole blood may be more sensitive than platelet-poor plasma, which might underestimate circulating viral load. Early eradication of viremia from platelets is associated with higher rates of SVR. Our data, reconfirm higher HCV-RNA levels in serum compared to platelets. Thrombocytopenia occurring during interferon-based therapy might be a manifestation of viral eradication rather than adverse effects. Our findings warrant testing the sensitivity of platelet viral load as a predictor of poor response.