Unspecific reactivity of IgM directed against the low-molecular-weight antigen of Toxoplasma gondii

• Published in: European journal of clinical microbiology & infectious diseases Vol. 22; no. 7; pp. 418 - 421
• Main Authors: DAO, A, AZZOUZ, N, ELOUNDOU NGA, C, DUBREMETZ, J. F, SCHWARZ, R. T, FORTIER, B
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.07.2003; Springer Nature B.V
• Subjects: Animals; Antibodies, Protozoan - immunology; Antigens, Protozoan - immunology; Bacteria; Biological and medical sciences; Cercopithecus aethiops; Female; Human protozoal diseases; Humans; Immunoglobulin M - immunology; Infectious diseases; Medical sciences; Parasitic diseases; Pregnancy; Protozoal diseases; Toxoplasma - chemistry; Toxoplasma - cytology; Toxoplasma - immunology; Toxoplasmosis; Vero Cells; Human; Protozoa; Apicomplexa; Protozoal disease; False positive; Serology; Parasitosis; IgM; Infection; Antigen; Specificity; Toxoplasma gondii; Toxoplasmosis
• ISSN: 0934-9723; 1435-4373
• DOI: 10.1007/s10096-003-0948-9

During routine serological survey, eight patients (5 pregnant women, 3 grafted patients) were positive for Toxoplasma gondii-specific IgM by enzyme-linked immunoassay but negative by a simultaneously performed immunosorbent agglutination assay. No clinical or biological symptoms of toxoplasmosis were observed later, despite the absence of treatment. Only one IgM-reactive band, which corresponded to the low-molecular-weight antigen of Toxoplasma gondii, was observed by Western blotting of these patients' sera. Dot blotting of lipid extracts of Toxoplasma gondii demonstrated that this reactivity was directed against sphingolipids or ceramides. This IgM positivity, which is unrelated to acute toxoplasmosis, raises strong concerns about the possibility of misleading results of this test in the diagnosis of toxoplasmosis in humans.