Prevalence of Congenital Toxoplasma gondii Infection among Newborns from the Poznań Region of Poland: Validation of a New Combined Enzyme Immunoassay for Toxoplasma gondii-Specific Immunoglobulin A and Immunoglobulin M Antibodies
AUTOR(ES)
Paul, Małgorzata
FONTE
American Society for Microbiology
RESUMO
We determined the value of a new serological assay detecting Toxoplasma-specific immunoglobulin M (IgM) and IgA antibodies at birth for use in mass neonatal screening. The incidence of congenital infection in newborns was compared with data from an epidemiological investigation on the seroprevalence of Toxoplasma in the studied population. Peripheral blood was collected on Guthrie cards during the first 3 days of life and tested for anti-Toxoplasma IgA and IgM using a noncommercial immunocapture enzyme-linked immunosorbent assay (ELISA). When the screening assay was positive, serum samples from the child and the mother were collected for use in Western blotting comparative immunological profile analysis and traditional serological tests for determination of specific IgG, IgM, and IgA antibodies. From December 1998 to April 2000, 17,653 filter paper samples from live-born neonates were successively screened. Congenital T. gondii infection was finally confirmed in 19 newborns. In traditional assays, 13 of 19 infants were IgM and IgA positive using filter paper eluates at birth, 1 child was positive only for IgM, 1 patient was positive for IgM and borderline for IgA, 1 had an equivocal level of IgA, and 3 cases were confirmed only by the Western blot assay. The prevalence of Toxoplasma-specific IgA and/or IgM in filter paper samples at birth was 1 per 929 live-born neonates (1.08/1,000) or about 1 per 523 children (1.9/1,000) born to nonimmune women with a potential risk of primary T. gondii infection during pregnancy, compared to the actual seropositivity rate of 43.7%. The diagnostic sensitivity of the combined IgA-IgM ELISA using neonatal filter paper specimens was not more than 95%, the positive predictive value of the test was 82.6%, and the diagnostic specificity was calculated to be 99.9%. The combined IgA-IgM ELISA is a valuable method for the diagnosis of congenital toxoplasmosis at birth and fulfills criteria for neonatal screening programs. The method showed a good diagnostic sensitivity in neonates untreated prenatally who were born in an area of high seroprevalence of T. gondii infection.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=88047Documentos Relacionados
- Recombinant Antigens To Detect Toxoplasma gondii-Specific Immunoglobulin G and Immunoglobulin M in Human Sera by Enzyme Immunoassay
- Human Toxoplasma gondii-specific secretory immunoglobulin A reduces T. gondii infection of enterocytes in vitro.
- Usefulness of Toxoplasma gondii-Specific Recombinant Antigens in Serodiagnosis of Human Toxoplasmosis
- Reverse enzyme immunoassay for detection of specific anti-Toxoplasma immunoglobulin M antibodies.
- Expression of Toxoplasma gondii-Specific Heat Shock Protein 70 during In Vivo Conversion of Bradyzoites to Tachyzoites