Antibody to Toxocara canis in the aqueous humor

The aqueous humor and serum samples of patients with presumed ocular toxocariasis were examined by an enzyme-linked immunosorbent assay (ELISA) for antibody to the embryonated egg antigen. Using a single dilution (1:8), higher amounts of antibody have been found in the aqueous humor than in the serum samples. Antibody was not found in the serum or aqueous humor of patients with retinoblastoma, Coats' disease, uveal malignant melanoma, or central retinal artery obstruction. While two patients with presumed ocular toxocariasis had normal serum levels of antibody, the aqueous humor ELISA titers were greatly elevated, supporting the clinical diagnosis and suggesting localized antibody production.