Alteration of serum thrombopoietin levels in patients with chronic hepatitis C under interferon therapy.

Thrombocytopenia is commonly observed during interferon-alpha (IFN-alpha) therapy in patients with chronic hepatitis C. Since thrombopoietin (TPO) is the main regulator of thrombopoiesis, thrombocytopenia may partially be due to a reduced TPO generation. Because of the developments of the second generation of TPO mimetic drugs patients with reduced TPO levels should be identified possibly having a benefit by medicinal stimulation of thrombopoiesis. Therefore, platelet count and serum TPO concentration of patients receiving an interferon-alpha therapy were determined.Twelve patients treated with IFN-alpha (daily 10 x 106 IU s.c. for four weeks) in cause of chronic hepatitis C were examined during the first month of therapy. Serum TPO concentration significantly decreased from 80.8+/-48.0 to 34.6+/-24.5 pg/ml (p<0.05, Mann-Whitney test), and platelet count declined from 214,417+/-48,292 to 151,333+/-44,726 platelets/microl. During the following three weeks platelet count remained at a low level, while serum TPO increased to normal range.In conclusion, an interferon treatment causes reduced serum TPO level during the first week of therapy accompanied by decreased platelet count. The reduction in TPO synthesis contributes to the development of thrombocytopenia in patients during interferon therapy.