Nk-associated receptors on Cd8 T cells from treatment-naive Hiv-infected individuals: defective expression of Cd56

Objectives: This study addresses the detailed expression of natural killer (NK)-associated receptors on CD8 T lymphocytes in treatment-naive HIV-infected individuals. Design: Experimental study analysing the expression of NK-associated receptors on peripheral blood T lymphocytes from HIV-infected individuals compared with healthy controls. Methods: Flow cytometry was used to analyse the expression of CD56, CD16, CD94, NKG2A, NKB1, CD161, CD244, and perforin, according to the CD28 phenotype, on CD8 bright T cells obtained from treatment-naive HIV-infected individuals and from healthy controls. Results: The results showed that CD8 bright T cells from treatment-naive HIV-infected individuals had a decreased expression of CD56 and that CD8 bright CD56 cell numbers correlated with CD4 cell counts. NK-associated markers were preferentially expressed on CD8 bright CD28 negative T cells, both in healthy controls and HIV-infected individuals. An increased expression of CD94, CD244, and perforin, which was the consequence of the expansion of the CD8 bright CD28 negative T-cell subset, was also observed in HIV infection. Conclusions: As the CD8 bright CD56 T cells are the mature cytolytic effector cells, the defective expression of CD56 on CD8 bright T cells shown in HIV-infected individuals could be involved in the decreased peripheral blood T-cell cytotoxicity found in HIV infection.