Rejection in lung transplantation--an immunohistochemical study of transbronchial biopsies.

The number, distribution, and phenotype of mononuclear cells infiltrating the allograft lung transplant were determined immunohistochemically with monoclonal antibodies directed against cellular antigens (CD3, CD4, CD8, CD22, CD25, CD16, CD56, CD68, HLA-DR) on frozen sections of transbronchial biopsies. Seventy-two transbronchial biopsies from 21 patients undergoing lung or heart-lung transplantation were evaluated histologically and immunohistologically in a prospective study. Four major results were obtained in the graft lung parenchyma: (1) whatever the histological grading of rejection, T lymphocytes expressing CD3 were present and in a significantly higher number than in control subjects (P < 0.0005); (2) there was a positive correlation between histological rejection and the number of CD3+, CD8+, CD25+, CD16+ cells (P < 0.01); (3) the CD4/CD8 ratio was inverted (0.52 +/- 0.04), with no correlation with the histological rejection; and (4) the number and location of CD3+, CD25+ cells did not correlate with CMV identification in bronchoalveolar lavage. Immunohistochemical criteria could be used for diagnosis of rejection in the management of heart-lung transplantation.