Late-onset interstitial pneumonia following allogeneic bone marrow transplantation

Although most episodes of interstitial pneumonia (IP) following allogeneic bone marrow transplantation occur during the second or third month, occasional cases occur later. The records of 139 patients transplanted for leukemia over 6 years were reviewed in this study to examine cases of IP occurring beyond 100 days following marrow transplantation. Ten episodes of IP occurred among the 67 patients who survived 100 days (an actuarial probability of 18%). All cases occurred within the first year. An infectious cause was established in 80%. The case fatality rate was 60%. Although most infectious cases of IP occurring before 100 days are caused by cytomegalovirus, the late-onset cases in this study were caused by a heterogeneous group of pathogens, some of which were amenable to specific therapies. Thus, an aggressive approach to establishing a specific diagnosis should be made in cases of IP occurring more than 100 days after marrow transplantation.