Difference in onset between cytomegalovirus and idiopathic interstitial pneumonitis following allogeneic bone marrow transplantation for leukemia.

Interstitial pneumonitis is one of the major causes of morbidity and mortality following bone marrow transplantation (BMT). Based on the Japanese BMT Registry, however, since 1983 the incidence of interstitial pneumonitis at one year has decreased to 32% by means of several efforts, such as fractionated low-dose rate total body irradiation, selection of platelet donor from cytomegalovirus (CMV) seronegative donor, and prophylactic administration of anti-CMV high titer globulin. Cytomegalovirus (58%) was the most frequently causative organism within 100 days after bone marrow transplantation. On the other hand, idiopathic interstitial pneumonitis (44%) was the leading cause more than 100 days after bone marrow transplantation. There was a significant difference in onset after bone marrow transplantation against leukemia between cytomegalovirus (mean: 90 +/- 15 days) and idiopathic interstitial pneumonitis (mean: 186 +/- 32 days) (p less than 0.01).