CD8+CD45RA+ T lymphocytes present two distinct subpopulations expressing the CD11a molecule (LFA-1 α chain) with different intensity. CD11a(dim) cells represent the unprimed population within the CD8+CD45RA+ subset, whereas CD11a(bright) cells are activated and may be considered as memory lymphocytes. The aim of this study was to analyze the expression of CD11a and CD18 within the CD8+CD45RA+ population in young HIV-infected individuals at different stages of disease as a marker of activation and of disease progression. Blood cells from 82 HIV-infected individuals and 23 age-matched healthy controls were stained with unconjugated CD11a, CD18, PE-goat F(ab')2 anti-mouse, FITC-CD45RA, and TRI-Color CD8. Quantitative analysis for three- color immunofluorescence was carried out by flow cytometry. HIV+ subjects were subdivided into three groups according to their CD4+ cell number (group A, CD4+ cells > 500/μl [20 subjects], group B, CD4+ cells between 500 and 200/μl [36 subjects], and group C, CD4+ lymphocytes <200/μl [26 subjects]). We found a significant increase of CD11a(bright) in the CD8+CD45RA+ subpopulation throughout the progression of the disease. The CD11a(bright) percentage of positivity (mean) within the CD8+CD45RA+ subpopulation was 31% in healthy donors, 51% in group A, 52% in group B, and 68% in group C. CD11a(bright) expression was closely related to CD18(bright) (p <0.001), but not to CD38. The relative increase of CD11a and CD18 expression in CD8+CD45RA+ T lymphocytes parallels the decrease of CD4+ cells and the progression of disease: an inverse correlation between the percentages of CD4+ cells/μl and CD8+CD45RA+CD11a(bright) cells (p <0.001) and a direct correlation between the number of CD4+ lymphocytes per microliter and both the number of CD8+CD45RA+CD11a(dim) cells (p <0.001) and the number of CD8+CD45RA+CD11a(bright) (p = 0.002) was observed. The relative increase of CD8+CD45RA+CD11a(bright) cells may represent an additional marker for monitoring HIV-induced immunodeficiency.
|Number of pages||7|
|Journal||AIDS Research and Human Retroviruses|
|Publication status||Published - 1995|
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