title: Distinct alterations in the distribution of CD45RO+ T-cell subsets in HIV-2 compared with HIV-1 infection.
abstract: OBJECTIVE
  Some clinical studies indicate that disease progression in HIV-2-infected subjects may be slower than in HIV-1. We investigated 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 flow cytometry in peripheral blood mononuclear cells from healthy controls, HIV-1-(n = 49) and HIV-2-infected (n = 47) individuals divided into two groups: asymptomatic (ASY)/persistent generalized lymphadenopathy (PGL) and AIDS-related complex (ARC)/AIDS.
  
  
  RESULTS
  Both HIV-1- and HIV-2-infected patients had significant reductions in the absolute number and percentage of CD4+ lymphocytes compared with seronegative individuals. 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 differences in the degree of reduction of CD4+CD45RO+ cells in ASY/PGL HIV-1 versus HIV-2 patients. However, in HIV-1-infected ARC/AIDS individuals the reduction in the percentage of this subset was more pronounced than in HIV-2 infection and this difference reached statistical significance. The increase in CD8+ lymphocytes (percentage and absolute number) was 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-infected patients, whereas HIV-2-infected ASY/PGL patients had normal levels of these cells and HIV-2-infected ARC/AIDS patients had increases that were much less pronounced than that observed in HIV-1-infected ARC/AIDS patients. Significant differences in the absolute number and percentage of this subset between HIV-1- and HIV-2-infected individuals in similar clinical stages were found.
  
  
  CONCLUSIONS
  HIV-2-infected individuals 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.
authors.affiliation: Department of Medicine 2/Clinical Immunology, Faculty of Medicine of Lisbon, Santa Maria Hospital, Portugal.
authors.forename: A C
authors.initials: AC
authors.lastname: Jaleco
authors.forename: M J
authors.initials: MJ
authors.lastname: Covas
authors.forename: L A
authors.initials: LA
authors.lastname: Pinto
authors.forename: R M
authors.initials: RM
authors.lastname: Victorino
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes; D018414:CD8-Positive T-Lymphocytes; D005434:Flow Cytometry; D015658:HIV Infections / Q000097:blood / Q000276:immunology*; D015497:HIV-1; D015498:HIV-2; D006801:Humans; D007156:Immunologic Memory; D066298:In Vitro Techniques; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D017493:Leukocyte Common Antigens