PULMONARY CAPILLARITIS - A POSSIBLE HISTOLOGIC FORM OF ACUTE PULMONARY ALLOGRAFT-REJECTION

Acute rejection after lung transplantation occurs commonly and is usua lly characterized histologically by a perivascular mononuclear infiltr ate. We report five cases of pulmonary capillaritis with a histologic appearance distinct from typical rejection, occurring in patients rang ing in age from 18 to 45 years, with a variety of underlying diseases including alpha(1) antitrypsin deficiency, pulmonary hypertension, cys tic fibrosis, and rheumatoid arthritis. Four of the five patients had alveolar hemorrhage histologically, and two had frank hemoptysis. Time of onset ranged from 3 weeks to many months after transplantation. Th ree cases were fulminant, and there were two deaths. In only one case, with methicillin-resistant Staphylococcus aureus bronchitis, could in fection be established. All were treated with intensification of immun osuppressive therapy. Plasmapheresis was carried out in two cases and coincided with temporary improvement, but its efficacy was questionabl e because of concurrent immunosuppressive therapy. Two had recurrent b iopsy-proven acute rejection within 6 weeks of treatment, and one had recurrent severe pulmonary hemorrhage that abated with total lymphoid irradiation. Our experience suggests that pulmonary capillaritis in lu ng transplant recipients can be an acute, fatal illness with the poten tial for recurrence in the survivors. We speculate that it represents a form of acute vascular rejection, Early pathologic diagnosis and agg ressive immunosuppressive therapy are recommended. Although a humoral component was not documented, the possible response to plasmapheresis requires continued evaluation.