PCR for detection of rubella virus RNA in clinical samples.

A reverse transcription nested PCR (RT-PCR) assay for the detection of rubella virus RNA using primers from the E1 open reading frame was established. This assay was found to be sensitive (detecting approximately two synthetic RNA copies and RNA extracted from 0.1 50% tissue culture infective dose of rubella virus) and specific; five wild-type rubella strains and four vaccine strains were detected, and no nonspecific amplification of 16 other RNA viruses or RNAs from seven cell types occurred. Rubella virus RNA was detected in 12 pharyngeal swabs from patients with serologically confirmed rubella; these RT-PCR results were in complete agreement with virus isolation. Analysis of products of conception obtained after confirmed primary maternal rubella infection by RT-PCR gave 92% agreement (12 of 13 samples) with virus isolation. No false-positive results were obtained. The potential use of this assay for prenatal diagnosis of congenital rubella infection and for investigating aspects of the pathogenesis of chronic disease is discussed.