Value of routine surveillance cultures for detection of CMV pneumonitis following bone marrow transplantation.

The results of 5018 surveillance cultures for the detection of cytomegalovirus (CMV) from 177 patients undergoing allogeneic T cell-depleted bone marrow transplantation (BMT) were analysed to determine their value in predicting future development of CMV pneumonitis. Twenty-two patients were diagnosed as having CMV pneumonitis. The median times of a positive CMV culture result from urine, saliva or blood before disease in these patients were 32, 8 and 23 days, respectively. The positive predictive value of CMV viraemia for the development of CMV pneumonitis was 0.64. Multivariate analysis showed that recipient pretransplant CMV seropositivity and increasing recipient age were independent risk factors for CMV pneumonitis. By contrast, donor CMV seropositivity was protective against disease, supporting the hypothesis that immunity against CMV can be adopted from donor T cell-depleted marrow. It is concluded that detection of CMV viraemia in a surveillance protocol can predict subsequent CMV pneumonitis but that it is of low sensitivity. This might be improved by more frequent sampling or by the use of a more sensitive assay, such as the polymerase chain reaction, thus identifying individuals who may benefit from 'pre-emptive' therapy.