The importance of primary cytomegalovirus infection in childhood cancer.

Sixty-eight paediatric patients with malignant tumours or leukaemia were followed for signs of infection with human cytomegalovirus (HCMV) over 1 year. HCMV was isolated from 24 out of 68 patients at some point during the observation period; from urine in 14, from both urine and throat in 9 patients, and from throat alone in 1 patient. Previous antibody analysis indicated the presence of HCMV antibodies in 10 of the 24 virus-shedding patients, while 7 patients were seronegative and 7 undefined. Thus the incidence of reactivation appears to be higher than that of primary infection in these immunocompromised patients. The mean duration of virus shedding was 4.2 months in the primary infection group, 1.7 months in the reactivation group and 1.1 months in the undefined group. No difference in the incidence of HCMV-associated illness was observed between patients with leukaemia and those with malignant tumours. Clinical symptoms associated with HCMV infection (pneumonia (2), fever (6) and hepatitis (1)) were observed in all patients with primary infections and in only five patients with reactivated infection.