ROLE OF SPECIFIC IMMUNOGLOBULIN-E IN DIAGNOSIS OF ACUTE TOXOPLASMA INFECTION AND TOXOPLASMOSIS

Toxoplasma immunoglobulin E (IgE) antibodies were evaluated in an immu nosorbent agglutination assay (ISAGA) and an enzyme-linked immunosorbe nt assay (ELISA) to determine their usefulness in the diagnosis of acu te infection with Toxoplasma gondii. IgE antibodies were not detected in serum specimens from otherwise seronegative individuals, individual s with chronic toxoplasma infection, or infants without congenital tox oplasmosis. In contrast, they were detected in pregnant women who sero converted during gestation (100% by ELISA, 63% by ISAGA), patients wit h toxoplasmic lymphadenopathy (96% by ELISA, 88% by ISAGA), infants wi th signs of congenital toxoplasmosis which prompted serologic testing in the postnatal period (92% by ELISA, 67% by ISAGA), children and adu lts with toxoplasmic chorioretinitis (36% by ELISA, 18% by ISAGA), and adult patients with AIDS and toxoplasmic encephalitis (33% by ELISA, 25% by ISAGA). In many of the serum specimens, the titer of IgE antibo dies detected by the ISAGA were close to or at the positive cutoff val ue. The duration of detectable IgE antibodies in patients with acute i nfections varied considerably among individuals but showed a trend tow ard a briefer duration by the ISAGA than by the ELISA. These results r eveal that recrudescence of IgE antibodies in patients with reactivate d chronic infection (toxoplasmic chorioretinitis and toxoplasmic encep halitis) may be useful diagnostically and that demonstration of toxopl asma IgE antibodies is a useful adjunct to currently available serolog ic tests for the diagnosis of acute toxoplasma infection and toxoplasm osis.