Post-lung transplant biopsies: an 8-year Loyola experience

A total of 125 transplant procedures involving the lung have been performed at Loyola University of Chicago in 120 patients. There were 67 single (40 right, 27 left), 44 bilateral single, 2 double lung, and 12 heart-lungs (HL) transplant procedures. This paper summarizes the pathologic findings in 565 transbronchial, 102 endobronchial, 20 open lung, and 92 endomyocardial biopsies and compares them with the recommendations in the published literature. The lung biopsies were evaluated according to the Working Formulation, Lung Rejection Study Group, International Society of Heart Transplantation. In transbronchial biopsies, all of which were from the transplanted lungs, the number of alveolated lung fragments ranged from 0 to 14 (mean, 5). Two hundred twelve biopsies showed no rejection, 113 had minimal rejection, 133 had mild rejection, 34 had moderate rejection, and 1 had severe acute rejection. Active airway damage (Grade B) was seen in 48 biopsies, which were graded from minimal to severe based on the amount of inflammation. Chronic rejection (Grade C) was diagnosed in 23, chronic vascular rejection (Grade D) in 8, and acute vasculitis (Grade E) in 9 biopsies. Routine trichrome and elastic van Gieson stains did not add to the diagnosis. All biopsies were routinely stained with immunoperoxidase for cytomegalovirus. Cytomegalovirus was diagnosed in 84 biopsies, 54 by both H&E and immunoperoxidase, 23 by immunoperoxidase alone, and 5 by H&E alone. The endobronchial biopsy of the anastomotic site had nonspecific inflammation in 46 biopsies. Twenty-nine had infection with a specific organism, Aspergillus and Candida in each of 8 biopsies by Gomori's methenamine silver stain, cytomegalovirus in 7 (4 by H&E and immunoperoxidase; 3 by immunoperoxidase), bacteria in 4, and fungal hyphae in 2 biopsies. In the 12 patients with heart-lung transplants, a total of 92 endomyocardial, 35 transbronchial, and 1 endobronchial biopsies were obtained. Acute rejection was seen only in 2 endomyocardial biopsies, whereas the transbronchial biopsy showed acute mild or moderate rejection in 10, chronic rejection in 1, and cytomegalovirus infection in six biopsies. We conclude that: (a) all biopsies with alveolated lung parenchyma can be evaluated for rejection and infection yielding clinically significant diagnoses; (b) sections from three levels stained by H&E are essential for evaluation; (c) routine Gomori's methenamine silver, elastic van Gieson, and trichrome stains are not required for transbronchial biopsy, however, routine Gomori's methenamine stain is recommended for all anastomotic site biopsies; (d) routine immunoperoxidase for cytomegalovirus is extremely helpful; (e) Grade B rejection should be further graded; and (f) endomyocardial biopsy played no significant role in the management of heart-lung recipients.