Immunohistochemical localization of ganciclovir in the human retina

Purpose. To localize ganciclovir in the retina of human eyes treated with intravenous or intravitreal ganciclovir for cytomegalovirus (CMV) retinitis. Methods. Paraffin-embedded five-micron sections of autopsy eyes were obtained from seven patients as follows: two patients with CMV retinitis treated with intravenous ganciclovir; two patients with CMV retinitis treated with an intravitreal sustained-release ganciclovir device; one patient with CMV retinitis treated with intravenous foscarnet; and two patients with AIDS without CMV retinitis who did not receive any anti-CMV therapy. The paraffin was removed from the sections, and indirect immunofluorescent staining was performed, using an antiserum to ganciclovir. Results. Bright fluorescent staining was noted in the retinal pigment epithelium (RPE) and photoreceptor outer segments of eyes treated with intravenous or intravitreal ganciclovir, but not in eyes treated with foscarnet or without CMV retinitis. In addition, patches of bright fluorescent staining of the internal limiting membrane was noted in eyes treated with intravitreal ganciclovir. Conclusions. Ganciclovir is detected in the outer retina of patients with CMV retinitis treated with intravenous or intravitreal therapy. The drug is detected also in the internal limiting membrane in eyes treated with the intravitreal sustained-release ganciclovir device.