Aqueous tap and rapid diagnosis of cytomegalovirus anterior uveitis: the Reggio Emilia experience

Purpose: The diagnosis of cytomegalovirus (CMV) anterior uveitis in immunocompetent patients requires confirmation by polymerase chain reaction (PCR) analysis and/or intraocular antibody index (AI) assay. In this study, we analyzed the different contributions of PCR and AI to CMV diagnosis by performing one single aqueous tap. Methods: A retrospective chart review was conducted of HIV-negative patients attending the Ocular Immunology Unit of Azienda Unità Sanitaria Locale - IRCCS, Reggio Emilia, Italy, from March 2015 to April 2018 with a diagnosis of hypertensive anterior granulomatous uveitis compatible with suspected CMV etiology. Diagnosis was confirmed by real-time PCR (RT-PCR) and intraocular antibody production against CMV on aqueous humor samples. Clinical features were compared to antibody titer and diagnostic delay. Results: Twenty-three patients with suspected CMV uveitis (13 males, 10 females, mean age 48 ± 16 years) were included in the analysis. AI was positive in 20/23 (87%) samples, and PCR tested positive in 9/23 (39%). By combining both tests, the sensitivity was 100%. Median diagnostic delay was 29 months (IQR 9-107). Diagnostic delay and antibody titer were significantly associated with glaucoma (r = 0.714, p < 0.0001; r = 0.476, p = 0.02, respectively). Conclusions: Our data suggest that to improve the diagnostic accuracy of CMV anterior uveitis, PCR and AI are both useful and complimentary. In our series, AI was the most sensitive diagnostic tool. One single aqueous tap is sufficient to achieve 100% sensitivity in CMV diagnosis. Early diagnosis is necessary to prevent the development of glaucoma.