[Prevention and diagnosis of congenital syphilis from an immunological viewpoint].

Frequency of syphilitic infection among 5772 pregnant women in the Düsseldorf area was 0.4%. Of 91 mothers with a positive Treponema pallidum haemagglutination (TPHA) test, 23 required treatment. Congenital syphilis was found only in those children whose mothers were not known to have syphilis at the time of birth. Diagnosis of Treponema infection in the newborn can be made with certainty only if there is a positive IgM-antibody test. In the absence of Treponema pallidum-specific serum IgM-antibodies in the newborn or if a positive IgM-test is not plausible, the suspected diagnosis can be confirmed or excluded only by serial post-partum tests of antibody kinetics. In TPHA the test reacting IgG-antibodies are eliminated in non-infected infants with a half-life of 20.5 days. Prolonged elimination half-life or persistence of positive TPHA titres confirms intra-uterine or perinatal syphilitic infection.