DISTINCT ALTERATIONS IN THE DISTRIBUTION OF CD45RO-CELL SUBSETS IN HIV-2 COMPARED WITH HIV-1 INFECTION( T)

Objective and design: Some clinical studies indicate that disease prog ression in HIV-2-infected subjects may be slower than in HIV-1. We inv estigated whether there were differences in the distribution of CD45RO + (memory) and CD45RA+ (naive) T-cell subsets between HIV-1 and HIV-2 infection. Methods: Analysis of lymphocyte subsets was performed by fl ow cytometry in peripheral blood mononuclear cells from healthy contro ls, HIV-1-(n = 49) and HIV-2-infected (n = 47) individuals divided int o two groups: asymptomatic (ASY)/persistent generalized lymphadenopath y (PGL) and AIDS-related complex (ARC)/AIDS. Results: Both HIV-1- and HIV-2-infected patients had significant reductions in the absolute num ber and percentage of CD4+ lymphocytes compared with seronegative indi viduals. No significant differences were found between HIV-2- and HIV- 1-infected subjects in the same clinical stage. CD4+CD45RA+ cells were significantly reduced in HIV-1 and HIV-2 ARC/AIDS patients and mildly reduced in ASY/PGL HIV-1 and HIV-2 patients. There were no difference s in the degree of reduction of CD4+CD45RO+ cells in ASY/PGL HIV-1 ver sus HIV-2 patients. However, in H1V-1-infected ARC/AIDS individuals th e reduction in the percentage of this subset was more pronounced than in HIV-2 infection and this difference reached statistical significanc e. The increase in CD8+ lymphocytes (percentage and absolute number) w as more pronounced in HIV-1 and the differences between HIV-1- and HIV -2-infected patients were statistically significant. CD8+CD45RO+ cells were significantly increased both in ASY/PGL and ARC/AIDS HIV-1-infec ted patients, whereas HIV-2-infected ASY/PGL patients had normal level s of these cells and HIV-2-infected ARC/AIDS patients had increases th at were much less pronounced than that observed in HIV-1-infected ARC/ AIDS patients. Significant differences in the absolute number and perc entage of this subset between HIV-1- and HIV-2-infected individuals in similar clinical stages were found. Conclusions: HIV-2-infected indiv iduals exhibit a lesser degree of depletion of memory CD4+ cells and a more limited expansion of CD8+CD45RO+ subset, which could be related to the putative lower immunopathogenicity of HIV-2.