title: Assessment of the value of detecting specific IgA antibodies for the diagnosis of a recently acquired primary Toxoplasma infection.
abstract: OBJECTIVE
  To assess the value of detecting IgA antibodies for the diagnosis of a recently acquired primary Toxoplasma infection.
  
  
  METHODS
  IgA antibodies were screened in sera from 87 women with different serological profiles of Toxoplasma gondii IgM and IgG antibodies and Toxoplasma-specific IgG avidity. The IgM and IgG antibodies and the IgG avidity were measured with an automated Vitek Immuno Diagnostic Assay System (VIDAS). Anti-T.gondii IgA was measured with Platelia Toxo IgA TMB kits.
  
  
  RESULTS
  All 12 sera obtained from women with clinical and/or serological evidence of a recently acquired Toxoplasma infection were positive for IgA. In 42 serum samples obtained more than 6 months after T. gondii infection from women with no clinical evidence of infection, but who had a positive IgM test and a high IgG avidity index, the IgA-enzyme linked immunosorbent assay (ELISA) test results were positive, negative, and doubtful in 16 (38.1%), 23 (54.8%), and 3 (7.1%) sera, respectively. In eight women, IgA was detected in sera collected more than 9 months after the onset of infection. The IgA test result was also positive in 11 of 12 sera (91.7%) obtained from women with no clinical evidence of toxoplasmosis, but who had a positive IgM test and a borderline IgG avidity index. The IgA-ELISA was negative in 21 sera obtained more than 2 years after the onset of T. gondii infection from women with no clinical evidence of toxoplasmosis, but who had a negative IgM test and a positive IgG test.
  
  
  CONCLUSIONS
  These results show that IgA is not a dependable marker for a recently acquired primary Toxoplasma infection.
authors.affiliation: Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.
authors.forename: Fernanda Santos
authors.initials: FS
authors.lastname: Nascimento
authors.forename: Lisandra Akemi
authors.initials: LA
authors.lastname: Suzuki
authors.forename: Cláudio Lúcio
authors.initials: CL
authors.lastname: Rossi
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D013997:Time Factors; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology
chemical_list: D007070:Immunoglobulin A