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

Abstract: HIV-1 seropositive patients often exhibit thrombocytopenia, considered of multifactorial aetiology. Thrombopoietin (TPO), a recently isolated cytokine, is the main regulator of megakaryocyte and platelet production. The objective of this study was to analyse serum TPO levels in thrombocytopenic and non-thrombocytopenic HIV-1 infected patients. Serum TPO levels were measured by ELISA in 43 healthy individuals and in 88 HIV-1 infected patients: 68 thrombocytopenics and 20 non-thrombocytopenics. Thrombocytopenic HIV-1 infected patients showed higher TPO concentrations (263 ± 342 pg/ml) than non-thrombocytopenics (191 ± 86 pg/ml); levels in both groups were significantly higher than those of healthy controls (121 ± 58 pg/ml). Two subgroups of thrombocytopenic patients, the autoimmune thrombocytopenic purpura (AITP) 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 differences in TPO levels between thrombocytopenic and non-thrombocytopenic patients were generally small. The finding of mildly increased TPO levels along with the recently described recovery of thrombocytopenia following recombinant TPO administration confirms the implication of ineffective platelet production in the origin of HIV-associated thrombocytopenia.