IgE and IgG antibodies in Toxocara canis infection. A clinical evaluation.

The relationship between IgE and IgG antibodies against the metabolic exoantigen of Toxocara canis (TEX antigen) in sera of selected patients with the ocular and visceral form of the disease have been investigated. The specificity and sensitivity of the TEX antigen employed in immunoenzymatic and radioimmunologic assays have been verified. Six hundred and forty-one sera from healthy donors were tested as controls. Our data emphasize the importance of IgE antibodies to ocular larva migrans syndrome and suggest that they play a significant role as a marker of infection. In the visceral form, IgG antibodies seem to mask the presence of IgE by a competitive mechanism toward the same epitopes of the parasite. In fact, IgE antibody titers increase after depletion of IgG from serum.