Immunopathology of Ascarid Infection of the Eye

The roles of IgE antiascarid antibodies and mast cells were compared in passively sensitized guinea pigs and animals infected intravitreally with ascarid larvae (Toxocara canis, Ascaris suum). Intravenous IgE antibody disappeared from the serum within 48 hours, but induced a hypersensitive state that persisted for 28 days. In systemically immunized animals, the aqueous-serum IgE antibody ratio was 1:1,000 or less. Passive periocular anaphylactic reactions produced an infiltration of neutrophils and eosinophils, degranulation of mast cells, and vascular leakage in periocular and episcleral tissues. Systemic anaphylaxis also produced degranulation of uveal mast cells, and infiltration of eosinophils, and vascular leakage in the choroid. Intraocular infection produced a transient decrease of mast cells that correlated with an increased infiltration of eosinophils and plasma cells.