Infectious complications within the first year after nonmyeloablative allogeneic peripheral blood stem cell transplantation.

Nonmyeloablative peripheral blood stem cell transplantation (PBSCT) is a novel therapeutic strategy for patients with malignant and non-malignant hematologic diseases. Infectious complications of this procedure have not been previously well described. Data on 12 patients transplanted at a tertiary care center were collected prospectively and verified retrospectively. Neutropenia developed in a third of patients, lasting for a median of 5 days. All patients developed some degree of graft-versus-host disease, as intended. Most patients achieved full chimerism by week 5. Bacterial infections occurred in two patients (17%). Cytomegalovirus (CMV) viremia occurred in five patients (42%) at a median of 80 days; none had received CMV prophylaxis. Viremia was associated with fever and fatigue in three patients, possible gastrointestinal involvement in one patient and was asymptomatic in one patient. All viremic patients responded to intravenous ganciclovir therapy. No fungal infections were documented. No patients died as a result of infection. The incidence of CMV viremia in our patients was high, but the incidence of invasive disease due to CMV was low. The best strategy to prevent CMV in patients undergoing nonmyeloablative PBSCT remains to be determined, but strategies employed in traditional allogeneic bone marrow transplantation should be considered in these patients.