Serum thrombopoietin levels in thrombocytopenic and non-thrombocytopenic patients with human immunodeficiency virus (HIV-1) infection

HIV-1 seropositive patients often exhibit thrombocytopenia, considered of m ultifactorial aetiology. Thrombopoietin (TPO), a recently isolated cytokine , is the main regulator of megakaryocyte and platelet production. The objec tive of this study was to analyse serum TPO levels in thrombocytopenic and non-thrombocytopenic HIV-1 infected patients. Serum TPO levels were measure d by ELISA in 43 healthy individuals and in 88 HIV-1 infected patients: 68 thrombocytopenics and 20 non-thrombocytopenics. Thrombocytopenic HIV-1 infe cted patients showed higher TPO concentrations (263 +/- 342 pg/ml) than non -thrombocytopenics (191 +/- 86 pg/ml); levels in both groups were significa ntly higher than those of healthy controls (121 +/- 58 pg/ml). Two subgroup s of thrombocytopenic patients, the autoimmune thrombocytopenic purpura (AI TP) group and the mild thrombocytopenic group, presented TPO levels similar to those of non-thrombocytopenics. Patients exhibiting pancytopenia showed the highest TPO concentrations. However, there was no correlation between TPO levels and platelet counts in any group of HIV-1 infected patients. TPO levels in HIV-1 seropositive patients were slightly increased and the diff erences in TPO levels between thrombocytopenic and non-thrombocytopenic pat ients were generally small. The finding of mildly increased TPO levels alon g with the recently described recovery of thrombocytopenia following recomb inant TPO administration confirms the implication of ineffective platelet p roduction in the origin of HIV-associated thrombocytopenia.