USE OF PCR FOR PRENATAL AND POSTNATAL DIAGNOSIS OF CONGENITAL-RUBELLA

A reverse transcription-nested PCR assay (RT-PCR) was evaluated for di agnosis of congenitally acquired rubella in utero and during infancy. RT-PCR was compared with virus isolation for retrospective detection o f rubella virus in placental and fetal tissues obtained after terminat ion of pregnancy following primary rubella or rubella virus reinfectio n, Concordant results were obtained for 85% of samples; rubella virus RNA was detected by RT PCR alone in four samples, and rubella virus wa s detected by isolation alone in two samples. Samples were also obtain ed for prenatal diagnosis of congenital infection; rubella virus RNA w as detected in three of seven chorionic villus samples and one of thre e amniotic fluid samples by RT-PCR, while rubella virus was isolated i n only one chorionic villus sample. To demonstrate that the RNA extrac ted from chorionic villus samples contained amplifiable RNA, a nested RT-PCR was used to detect keratin mRNA. Rubella virus was detected in the placenta in two cases in which the fetus was uninfected, and there was no evidence of rubella virus in the placenta from one case in whi ch the fetus was infected, Thus, detection of rubella virus in chorion ic villus samples by RT-PCR may not always correctly predict fetal rub ella virus infection, RT-PCR was successfully used for the diagnosis o f congenitally acquired rubella in infancy. Rubella virus RNA was dete cted in cyropreserved or formalin-fixed lens aspirates obtained from i nfants in India with serologically confirmed congenital rubella but no t in samples from controls with inherited cataract.