Chonmaitree T, Powell K R, Menegus M A
Pediatr Infect Dis. 1982 Jul-Aug;1(4):228-31. doi: 10.1097/00006454-198207000-00007.
Staphylococcal protein A (SPA) has been used to remove maternal IgG from cord or neonatal sera to make serologic testing for congenital infection more IgM specific. To evaluate the clinical usefulness of this procedure, sera sent for TORCH titers that had rubella hemagglutination inhibition (RHI) reciprocal titers greater than or equal to 8 or toxoplasmosis indirect fluorescent antibody (TFA) titers greater than or equal to 16 were adsorbed with SPA and retested. Nine of 109 sera were TFA positive by routine testing, and all but one from an infant with congenital toxoplasmosis became negative after SPA adsorption. A repeat TFA at 4 to 26 months of age was negative in all six children without evidence of toxoplasmosis who returned for follow-up. Fifty of 55 sera were RHI positive by routine testing, and all but one from an infant with congenital rubella became negative after SPA adsorption. The repeat routine RHI was negative in 32 of 35 children whose sera were initially negative after SPA adsorption. SPA adsorption greatly increased the specificity of routine RHI and TFA tests in the diagnosis of congenital rubella and toxoplasmosis.
葡萄球菌蛋白A（SPA）已被用于从脐带血或新生儿血清中去除母体IgG，以使先天性感染的血清学检测更具IgM特异性。为评估该方法的临床实用性，将风疹血凝抑制（RHI）效价大于或等于8或弓形虫间接荧光抗体（TFA）效价大于或等于16的送检TORCH效价的血清用SPA吸附并重新检测。109份血清中有9份经常规检测TFA呈阳性，除1例先天性弓形虫病婴儿外，其余所有血清经SPA吸附后均转为阴性。6名无弓形虫病证据且前来随访的儿童在4至26个月龄时重复检测TFA均为阴性。55份血清中有50份经常规检测RHI呈阳性，除1例先天性风疹婴儿外，其余所有血清经SPA吸附后均转为阴性。在SPA吸附后血清最初为阴性的35名儿童中，有32名儿童重复进行的常规RHI检测为阴性。SPA吸附大大提高了常规RHI和TFA检测在先天性风疹和弓形虫病诊断中的特异性。
