Lung biopsy evaluation of acute rejection versus opportunistic infection in lung transplant patients

The histopathologic changes of acute rejection in experimental and therapeutic lung transplantation have been described with emphasis on perivascular lymphocytic infiltrates. However, the clinical usefulness of these changes in the differentiation of acute rejection from opportunistic infection on lung biopsy is not clear. Since 1985, 5 single-lung, 2 double-lung, and 7 heart-lung transplants have been performed at the Methodist Hospital in Houston. Although some patients have had an unremarkable course, six have required intensive clinical evaluation on one or more occasions during the early postoperative period for the following signs and symptoms: unexplained fever, new infiltrates on chest roentgenogram, and/or deterioration in clinical status. Although adult respiratory distress syndrome and pulmonary hemorrhage can occasionally cause these findings, the major clinical differential diagnosis is acute transplant rejection versus opportunistic infection. As part of their evaluation, these 6 patients underwent a combined total of 14 lung biopsies (9 transbronchial, 5 open). We retrospectively studied the lung biopsies from these patients to determine the utility of lung biopsy in differentiating acute transplant rejection from opportunistic infection.