Background: Erythropoietin (EPO) not only stimulates erythropoiesis but also thrombopoiesis. As pegylated-interferon-alpha(PEG-IFN-alpha)-induced thrombocytopenia may become a limiting factor for continuation of therapy, the present study investigated if EPO can alleviate PEG-IFN-alpha induced thrombocytopenia. Further, we hypothesize that EPO increases platelet reactivity and protease activated receptor 1 (PAR-1) expression during combination antiviral therapy.
Methods: Forty patients with chronic hepatitis C received either 10,000 IU EPO 3 x/week or placebo in a randomized, placebo-controlled, double-blinded fashion for 4 wk and combination antiviral therapy with PEG-IFN-2a and ribavirin.
Results: EPO alleviated the decrease in hemoglobin during combination antiviral therapy with ribavirin (10%vs 20%, p < 0.0001). Platelet counts decreased stronger in EPO than in placebo group on day 28 (p= 0.007). EPO induced a 40% increase in PAR-1 (p < 0.0001), which was accompanied by 100% increase in platelet reactivity (p < 0.0001). PFA-100 platelet plug formation time and PEG-IFN-alpha-induced vWF-increase were not different between study groups.
Conclusions: Treatment with EPO alleviated the decrease in hemoglobin but worsened PEG-IFN-alpha induced thrombocytopenia after the first 4 wk of combination therapy. EPO caused PAR-1 receptor upregulation on platelets, which promoted an increase in platelet reactivity without affecting PFA-100 platelet plug formation time. EPO is not a useful option for short-term support of platelet production during antiviral therapy.