996 STAPHYLOCOCCAL PROTEIN A (SPA) IN THE EVALUATION OF POSSIBLE CONGENITAL INFECTION

Abstract

We have used SPA adsorption to remove maternal IgG from cord or neonatal sera to facilitate the diagnosis of congenital infection. To evaluate the clinical usefulness of this procedure, sera sent for “TORCH” serology that were rubella HI (RHI) or toxoplasmosis FA (TFA) positive were retested after SPA adsorption. RHI or TFA was repeated after 4 months of age.RHI titers were ≥1:8 in 47/53 (90%) sera sent for TORCH serology Jan-Nov 1980. At discharge from hospital, only 1 child was thought to have congenital rubella. After SPA adsorption 7/47 (15%) had detectable RHI antibody. All children RHI negative after SPA adsorption have been negative at ≥4 months of age. To date, 5 children with persistent RHI antibody after SPA adsorption have been retested at ≥4 months. The infant thought to have congenital rubella had a RHI of 1:64; another with multiple anomalies was 1:16; the rest were <1:8. From Jan 1979-Nov 1980, 10 of 110 sera sent for TORCH serology were TFA positive. After SPA adsorption only 1 specimen remained positive and this child had congenital toxoplasmosis. We conclude that infants RHI or TFA negative after SPA adsorption are unlikely to be infected with these agents. Children with residual antibody should be evaluated further. Using this simple technique, positive serology was shown to be unrelated to intrauterine infection for 85% of RHI positive sera and 90% of TFA positive sera.