[Special problems after lung transplantation: walking a tightrope between infection and graft rejection]

Between November 1992 and September 1999 84 lungs have been transplanted at University Hospital Zurich. Currently the 1-year survival rate is up to 85%. However, long-term success is limited by the development of chronic rejection in the form of bronchiolitis obliterans. The risk factors are repeated episodes of acute rejection and infections, due to cytomegalovirus in particular. Both can occur in asymptomatic patients and are sometimes detected only by transbronchial lung biopsy. At the Zurich Lung Transplant Centre biopsies are performed as surveillance biopsies in asymptomatic patients in the first 6 months after transplantation, for clinical indications and as follow-up biopsies after a pathological result. Open lung biopsies are performed for special indications only. We evaluated 408 transbronchial biopsies taken between November 1992 and September 1999. Relevant findings were present in 46% of biopsies in symptomatic patients. Relevant acute rejection episodes were diagnosed in 15% of surveillance biopsies. Overall, 72% of acute rejection episodes requiring therapy and 33% of biopsies detecting cytomegalovirus were found in surveillance biopsies. 7 of 11 late (> 45 days postoperative) and 1 of 5 early (< or = 45 days postoperative) open lung biopsies revealed new diagnoses. Transbronchial biopsy after lung transplantation is at present the gold standard for diagnosis of acute rejection and cytomegalovirus pneumonia of the lung.