HUMORAL (ANTIBODY-MEDIATED) REJECTION IN LUNG TRANSPLANTATION

To confirm the existence and characterize the pathologic features of h umoral (antibody-mediated) lung rejection, we prospectively studied 55 lung transplant recipients (24 male [44%] and 31 female [56%], age ra nge 14 to 69 years [mean 45]). The time between transplantation and bi opsy ranged from 2 to 1546 days (mean 274). We performed direct immuno fluorescence with C3, immunoglobulin M, and immunoglobulin G antibodie s on frozen sections of 106 transbronchial biopsies and one wedge biop sy and compared the results with 13 explanted lungs, one donor lung, a nd two controls. The histologic diagnoses of these 107 biopsies includ ed acute cellular rejection (62, 58% [minimal 23, mild 33, moderate 5, and severe 1]), chronic rejection (eight, 7%), chronic vascular rejec tion (two, 2%), acute vasculitis (five, 5%), cytomegalovirus pneumonit is (two, 2%), acute pneumonia (two, 2%), acute organizing pneumonia (t wo, 2%), diffuse alveolar damage (one, 1%), no evidence of rejection o r infection (30, 28%), lipoid pneumonia (one, 1%), and inadequate for histologic diagnosis (one, 1%). Eighty-nine of 106 (84%) transbronchia l biopsies, the wedge biopsy, and control lungs were satisfactory for direct immunofluorescence, because each contained alveolate lung paren chyma and arterioles or venules. There was no demonstrable immunofluor escence in the wall of the blood vessels or in the lung parenchyma in any case. We conclude that (1) transbronchial biopsies and wedge biops ies provide adequate material to evaluate humoral rejection, and (2) i n spite of the large population studied, the satisfactory material obt ained, and the wide range of histologic diagnoses, we could not demons trate the occurrence of humoral rejection in the lung.