Objective: To address the mechanisms of the thrombocytopoietic dysfunction that may follow HIV infection and to compare peripheral blood and bone marrow as sources of CD34 progenitor cells in HIV-infected patients.
Methods: The study used CD34 progenitor cells from 20 previously untreated HIV-infected individuals, 20 HIV-infected individuals treated with antiretroviral therapy and a control group of 20 HIV-uninfected healthy individuals to examine in-vitro megakaryocytopoiesis. There were no hematological abnormalities at baseline in the study groups. CD34 progenitor cells derived from peripheral blood and bone marrow were purified and cultured in medium containing thrombopoietin, interleukin-3, and interleukin-6. HIV-1 plasma viral load was determined by b-DNA technique. Expression of receptors for thrombopoietin, interleukin-3, and interleukin-6 was assessed on CD34 cells by flow cytometry, and numbers of receptors per single cell were calculated by Quanticalc software.
Results: Growth of megakaryocytopoietic colony-forming units (CFU-MK) were impaired in untreated HIV-infected individuals despite normal platelet counts. Viral load levels inversely correlate with CFU-MK growth and platelet counts. Antiretroviral drug-treated individuals showed normal megakaryocyte development. Similar results were obtained whether the CD34 progenitor cells derived from peripheral blood or bone marrow.
Conclusions: These findings suggest that megakaryocyte differentiation is impaired before the onset of overt thrombocytopenia in HIV-infected patients and provide evidence for a direct link between viral replication and perturbed megakaryocytopoiesis, which appears to be prevented and/or restored by antiretroviral therapy. The results indicate that peripheral blood represents a suitable source of CD34 hematopoietic progenitors for studies of megakaryocytopoiesis in HIV disease.
From the aDepartment of Internal Medicine, Clinical Immunology, Allergy and Respiratory Diseases, University Hospital Group, Ancona, Italy
bDepartment of Medical and Surgical Sciences, Italy
cHaematology Clinic, Marche Polytechnic University, Ancona, Italy
dDepartment of Pathology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
eOrthopedic Clinic, Marche Polytechnic University, Ancona, Italy.
Received 29 March, 2006
Accepted 12 May, 2006
Correspondence to Dr A. Costantini, Servizio Regionale di Immunologia Clinica e Tipizzazione Tessutale, Azienda Ospedaliero Universitaria Ospedali Riuniti di Ancona, via Conca n. 71, 60020, Ancona, Italy. E-mail: firstname.lastname@example.org