Characterization of reactivation of cytomegalovirus retinitis in patients healed after treatment with highly active antiretroviral therapy

Purpose: To delineate the immune parameters associated with reactivation of cytomegalovirus (CMV) retinitis in patients for whom highly active antiret roviral therapy (HAART) was not successful. Methods: Prospective, longitudinal observational study of a cohort of 102 p atients with CMV retinitis treated with HAART and being followed up at the AIDS Ocular Research Unit of the University of California, San Diego from N ovember 1995 to November 1998. The study included serial clinical and fundu s photographic examinations with CD4 T-lymphocyte counts and HIV Viral load measurements. Results: Forty-seven of the 102 patients with CMV retinitis responded to HA ART. Thirty-five of the patients were successfully withdrawn from anti-CMV therapy. During a median follow-up of 74.71 weeks (range, 4.86-144 weeks) a fter discontinuation of anti-CMV therapy, four patients experienced a react ivation of CMV retinitis. In each case, the CD4 count decreased before reac tivation to a median of 31.5 cells/mm(3) (mean, 31.25 cells/mm(3); range, 2 3-39 cells/mm(3)). The association between the CD4 count decreasing to less than 50 cells/mm(3) and reactivation of CMV retinitis was statistically si gnificant (P < 0.0003). Conclusion: Four patients treated with HAART experienced reactivation of CM V retinitis as their CD4 count decreased. The threshold CD4 count below whi ch reactivation of CMV retinitis occurred in patients for whom HAART was no t successful appeared to be 50 cells/mm(3). Despite an initial response to HAART, patients are still at risk for reactivation of CMV retinitis if thei r CD4 count decreases to less than 50 cells/mm(3). The HIV viral load did n ot appear to predict CMV reactivation.