T cell subsets and cytomegalovirus retinitis in human immunodeficiency virus-infected patients

A case-control study was done to investigate the relationship between T cell subsets and cytomegalovirus (CMV) retinitis in human immunodeficiency virus (HIV)-infected subjects with or without CMV retinitis and CD4⁺ cell counts of <0.050 X 10⁹/L. Cell surface markers on peripheral blood lymphocytes were evaluated using flow cytometry. Patients with CMV retinitis had significantly lower levels of CD8⁺ cells (median: 0.152 X 10⁹/L) compared with levels for controls (median: 0.296 X 10⁹/L, P < .001). Significant down-regulation of costimulatory molecule CD28⁺ and lymphocyte function-associated antigen-1 (LFA-1) expression was observed in patients versus controls (CD28⁺: 0.048 X 10⁹/L vs. 0.143 X 10⁹/L, P < .001; LFA-1: 0.238 x 10⁹/L vs. 0.400 x 10⁹/L, P < .001), but no significant differences were noted for NK cells. We propose that progressive loss of the CD3⁺ CD8⁺ cell subset and down-regulation of CD28 and LFA-1 accessory molecules are associated with an increased risk of CMV retinitis in HIV-infected patients.