Mucosal T-lymphocytes in central airways of lung transplant recipients

The immunohistochemical profile of mucosal lymphocytes was investigated in the central airways of lung transplant recipients. Bronchial and transbronchial biopsies (BB and TBB, respectively) and bronchoalveolar lavage for culture of bacteria and viruses were performed during a fibroscopic procedure in patients without evidence of chronic rejection, 3 to 10 mo after surgery. Analysis was restricted to samples without concurrent airway infection: 23 pairs of BB and TBB from 18 transplant recipients were analyzed. An immunohistochemical technique was used to identify and score mucosal cells that reacted with monoclonal antibodies against CD4, CD8, CD45-Ro (memory T-cells), and HLA-DR molecules. The same procedure was applied in nine nonsmoking control subjects (NS group). Data from transplant recipients were allocated to R+ (n = 11) or R- groups (n = 12), depending on the presence or absence of histologic evidence of acute rejection on TBB. A statistically significant depletion of every immunoreactive cell subset was observed in the R+ and the R- groups, but not in the NS group. Conversely, no significant difference for either score of immunoreactive cells were found between R+ and R- groups. The immunosuppressive regimen is suspected to play to play a major role in this depletion of bronchial mucosal T-cells. The acute lung rejection process does not appear to affect concurrently the immunohistochemical profile of immunoreactive cells in the bronchial mucosa.