Elevated nitric oxide level in aqueous humor of AIDS patients with cytomegalovirus retinitis.

Human cytomegalovirus (HCMV) retinitis is the most common ocular opportunistic infection in AIDS. It often leads to blindness if left untreated. The questions as to how HCMV infection causes retinal immunopathogenesis and visual destruction in AIDS patients have not been completely established. Here we reported that the nitric oxide (NO) levels in aqueous humor samples in 10 AIDS patients with CMV retinitis (104.3 +/- 27.1 microM) were higher than the levels in 7 AIDS patients without CMV retinitis (36.1 +/- 10.4 micro M; p < 0.001). After ganciclovir treatment, the NO level in the vitreous body of 5 patients declined dramatically (53.4 +/- 11.8 micro M). By using immunohistochemistry assay, we found that the aggregates of macrophages infiltrated in the CMV-infected retina of 4 AIDS patients. Moreover, the expression of inducible-form NO synthase was detected in the infected retina of these patients. These results suggest that NO production in the eye may play a fundamental role in the immunopathogenesis of AIDS patients with CMV retinitis.