HUMAN POLYOMAVIRUS IN PREGNANCY - A MODEL FOR THE STUDY OF DEFENSE-MECHANISMS TO VIRUS REACTIVATION

  • 1 January 1983
    • journal article
    • research article
    • Vol. 53  (2) , 289-296
Abstract
A longitudinal study of human polyoma virus infection in 71 pregnant women was carried out and the virological findings were correlated with changes in the defence system in the same patients. As reactivation of human polyoma viruses generally occurred late in the second trimester it was possible to distinguish between immunological changes which preceded the onset of reactivation and those which were secondary to the infection. Evidence of reactivation was detected in 26 women; all had high or rising antibody titers against BK or JC virus, but only 5 of these developed viruria. A positive correlation was observed between a high monocyte count in early pregnancy and subsequent virus reactivation. The virus excretors had significantly lower neutrophil counts than the women who had no evidence of virus reactivation. Women with serological evidence of virus activity but no viruria has significantly higher neutrophil counts than the non-activators. They also had stronger lymphocyte responses to phytohemagglutinin (PHA) than the virus excretors. Virus activators were found to have a significant lymphopenia in the third trimester compared to the non-activators. High antibody levels did not appear to inhibit virus excretion. Evidently, monocytosis may predispose to reactivation of human polyoma viruses in pregnancy. Ability to contain the virus once it had been activated, was associated with neutrophilia, and relatively vigorous in vitro reactivity of lymphocytes to PHA. Persistent lymphopenia was probably secondary to virus reactivation. The model on which this study is based could be adapted to investigate the causes of reactivation of other viruses. It may also help to identify risk factors in patients who are particularly susceptible to infection with opportunistic viruses.