Immunologic and Virologic Laboratory Parameters Associated With Active AIDS-Related Cytomegalovirus Retinitis in the Era of Highly Active Antiretroviral Therapy

Abstract

Purpose: : To describe relationships between laboratory test values and active AIDS-related cytomegalovirus (CMV) retinitis in the era of highly active antiretroviral therapy (HAART); and to investigate risk of reactivation during follow-up, based on these tests.

Methods: : We evaluated CD4+ T-lymphocyte (CD4) count, CD8+ T-lymphocyte (CD8) count, and HIV RNA blood (HIV) level for patients with CMV retinitis in the Longitudinal Study of Ocular Complications of AIDS (LSOCA) at diagnosis and at reactivation of retinal infection. Effects of HAART on these values were determined. Cox proportional hazards models were used to evaluate laboratory measures as risk factors for reactivation.

Results: : Median CD4 and CD8 counts and HIV levels at diagnosis (n=155) were 26 cells/µL, 312 cells/µL, and 4.9 log copies/mL, respectively. Patients on HAART vs. those not on HAART had higher median CD4 counts (35 vs. 18 cells/uL; p=0.03) and higher inter-quartile ranges (72 vs. 33 cells/uL; p=0.11). Reactivation occurred in 30% of patients; median CD4 and CD8 counts and HIV levels at reactivation were 11 cells/µL, 198 cells/µL, and 4.8 log copies/mL, respectively. Each parameter during follow-up was related to reactivation, but CD4 count (<50 vs. ≥50 cells/µL; RR=3.5, p<0.001) and nadir CD8 count (RR=0.77 per 100 cells/µL, p<0.001) were the strongest risk factors. CD4 counts <50 cells/µL had a positive predictive value of 62% at 6 months (95% confidence interval [CI]=45-77%); the negative predictive value for CD4 counts ≥50 cells/µL was 78% at 6 months (95% CI=67-87%). The median time to reactivation of disease among patients with CD4 counts <50 cells/µL was 1.6 years (95% CI=1.0-3.0).

Keywords: AIDS/HIV • cytomegalovirus