BK virus: II. Serologic studies in children with congenital disease and patients with malignant tumors and immunodeficiencies.

Sera of 451 children with congenital diseases and 185 tumor patients were tested for BK virus-specific antibodies by hemagglutination inhibition and IgM-immunofluorescence tests. Compared to age-matched control groups, higher percentages and significantly elevated geometric mean titers of HI antibodies were found in all patient groups tested. Of children under six months of age with congenital diseases such as dysplasia, cerebral defects, and hyperbilirubinemia and hepatosplenomegaly, 4.2% (17/402) had BK virus-specific IgM antibodies. No positive sera were found in 68 control sera. Of tumor patients 5--15 years of age, 8.6% (16/185) had IgM antibodies to BK virus. In the control group, 30% (3/99) had them. Serial serum samples from 76 tumor patients treated with cytostatic drugs showed seroconversion in three cases. No relationship between certain clinical features and BK virus infection was noted. Isolation of BK virus was successful from urines of two infants with connatal defects, six patients suffering from malignant tumors, and four patients with inherited immunodeficiencies.