ANALYSIS OF WESTERN BLOTTING (IMMUNOBLOTTING) TECHNIQUE IN DIAGNOSIS OF CONGENITAL-SYPHILIS

The diagnosis of congenital syphilis in apparently healthy infants con tinues to be problematic. Immunoglobulin M antibodies specific for a s ubset of Treponema pallidum antigens have been detected by Western blo tting (immunoblotting). In the present study we investigated the sensi tivity and specificity of this method. We tested 26 infants aged 0 to 4 months who fulfilled the accepted criteria for the diagnosis of cong enital syphilis. There were 14 symptomatic infants. Sera from 13 of th ese infants were positive for the 47-kDa treponemal antigen (92% sensi tivity). The remaining 12 infants were clinically asymptomatic when te sted at birth but subsequently displayed features consistent with the disease. Reactive blots (antibodies to the 47- and/or the 15-kDa antig ens) were noted in 10 of the 12 infants (83% sensitivity). Thirty infa nts whose mothers had syphilis were monitored and shown to be uninfect ed. Nonreactive blots were seen in sera from 27 infants, while sera fr om 3 older infants had false-positive tests (90% specificity). The Wes tern blotting technique is sensitive (even in the diagnosis of clinica lly inapparent cases) and, in the absence of immunoglubulin M rheumato id factor, is a useful confirmatory test for congenital syphilis.