Evidence of Active Cytomegalovirus Infection in Clinically Stable HIV-Infected Individuals with CD4+ Lymphocyte Counts Below 100/??l of Blood

Abstract

To determine the frequency and significance of cytomegalovirus (CMV) viremia and viruria in HIV-positive subjects with low CD4+ lymphocyte counts but with no clinical indications for culture, we studied 100 consecutive clinically stable subjects with CD4+ cells < or = 100/microliters of blood who agreed to culture of blood and urine. Serum was tested for CMV antibody, p24 antigen, neopterin, and liver enzyme concentrations, and patients were offered funduscopic examination. Subjects' records were reviewed an average of 9.1 months after enrollment for evidence of subsequent CMV retinitis. Three of the original cohort proved ineligible because of CD4+ count > 100/microliters; CMV antibody was present in 96% of the remainder. Isolation of CMV from blood was uncommon (2 of 93 seropositive subjects) whereas viruria occurred in 51.6%; likelihood of having a positive urine culture was significantly related to the subject's absolute CD4+ lymphocyte count: 60% for those with CD4+ < or = 50/microliters, vs. 26.1% for those with CD4+ 51-100/microliters. Neither serum p24 antigen nor neopterin was predictive of CMV in urine or blood. No subjects submitting to ophthalmologic exam had unsuspected CMV retinitis. Subsequent development of retinitis correlated with CMV viruria on entry: 13.5% if urine-positive, 1.9% if negative (p = 0.029; Fisher exact test).