Interpretation of intraocular and serum antibody levels in necrotizing retinitis

Intraocular antibodies have been measured as a diagnostic aid in necrotizing retinitis but interpretation of results may be difficult.

Vitreous or aqueous and serum immunoglobulin G antibodies to toxoplasmosis, cytomegalovirus, herpes simplex virus I and II, and varicella zoster virus were subjected to enzyme-linked immunosorbent assay in 27 patients with necrotizing retinitis and 15 control patients. A quotient was derived quantitating the amount of excess antibody in the eye compared to serum. Different interpretative rules were analyzed to determine which yielded the highest sensitivity and specificity.

The highest intraocular antibody relative to serum among the 4 antibodies correctly predicted the final clinical diagnosis in 21 of 27 patients, for a sensitivity of 78% and a specificity of 90%. Interpretive rules that relied on a high numeric value of the antibody quotient or did not consider the relative ranking of the four antibody quotients were less sensitive and specific because multiple antibodies were detected in most eyes. The technique was safe and rapid.

Interpretation of antibody titers in intraocular fluids is facilitated by testing several relevant antibodies and comparing the results. The technique may be helpful to diagnose necrotizing retinitis and to ascertain viral cause in acute retinal necrosis.