Peripheral blood pre-erythroidal cells in HIV-1 infection

Objectives: Pre-erythroid cells are present in cord blood and in peripheral blood during early childhood but not in adulthood. These cells were recently found to facilitate bacterial infections during early childhood but at the same time to suppress accompanying pro-inflammatory reactions through mechanisms dependent on the activity of arginase. HIV long term infected patients often exhibit hematopoietic alterations through mechanisms that include direct effect of HIV on progenitor cells including erythroid cells. The goal of our pilot study was to investigate the frequencies of pre-erythroid cells in peripheral blood in different stages of HIV infection and their association with immune activation. Methods: We have recruited HIV infected patients with different pattern of disease progression: LTNP, HIV progressors naive to antiretroviral therapy, patient on ART and healthy controls. PBMCs isolated from peripheral blood of these patients were used to assess the frequency of pre-erythroid cells and the expression of inflammatory marker (CD38) on CD8+ T cells by means of flowcytometry. Results: We demonstrate that HIV progressors show significantly higher frequency of pre-erythroid cells than the other tested groups . Patients on antiretroviral therapy are not different in this regard from healthy controls, whereas LTNP's show slightly increased numbers of these cells. Frequency of pre-erythroid cells was conversely correlated with the frequency of CD38+ CD8+ T cells only in naïve HIV progressors. Presence of significant number of pre-erythroid cells was frequently related to the status of HIV/HCV coinfection. Conclusion: Our study shows that pre-erythroid cells are present in peripheral blood of HIV-1 infected adult patients naive to antiretroviral therapy, and once present they correlate to low levels of immune activation and the status of HIV/HCV coinfection. Their presence might influence the state of immune activation and susceptibility to infections.