Human Congenital Rubella: The Relationship of Immunologic Aberration to Viral Persistence *

The occurrence of chronic viral infection in experimental animals is a wellrecognized, although poorly understood, phenomenon.Until recently chronic viral persistence in man has been appreciated more as a clinical curiosity, as, for example, in recurrent herpes simplex labialis, than as an important and possibly common factor in the cause of human disease.The finding of persistent virus excretion in some infants whose mothers had been infected with rubella virus during pregnancy has focused attention on the mechanisms of host resistance to virus infection and how they may become altered to permit chronic viral persistence.Postnatally acquired rubella infection follows a pattern that is characteristic of many human virus diseases.Following exposure of a susceptible host to virus there is a 13-to-21-day asymptomatic incubation period during which virus replication occurs throughout the body apparently unchecked.Unlike many viruses, rubella virus does not appear to induce a detectable serum interferon response.'With the appearance of clinical symptoms the virus excretion begins to decrease and neutralizing antibody levels begin to rise.It is apparent, although not conclusively proven, that termination of virus excretion is associated with the development of antiviral immunity.l.Maternal infection during the early stages of pregnancy carries with it a high risk of fetal infection and rna1formation.l.Of great interest has been the observation that a variable number of affected offspring excrete virus for several months after birth.Approximately 30% will continue to excrete virus beyond six months of age and occasionally virus may be recovered from the cataractous lens up to three years after birth.It is the object of this review to summarize the available information on the nature of virus-specific and nonspecific immune responses of infants with congenital rubella in an effort to explain the mechanism of chronic viral persistence in this syndrome.