Perforin and granzyme B expression is associated with severe acute rejection. Evidence for in situ localization in alveolar lymphocytes of lung-transplanted patients.

To evaluate rejection episodes in lung-transplanted patients, we analyzed 31 bronchoalveolar lavage specimens for lymphocyte levels and lymphocyte expression of two intracytoplasmic activation markers, perforin, the pore-forming lytic protein, and granzyme B, a member of the serine esterase family. Using anti-human granzyme B and perforin mAbs, we show that their expression in alveolar lymphocytes is correlated with the severity of rejection as assessed by histological parameters and the patients' clinical status. The presence of these molecules may provide a prognostic parameter that will facilitate the patients' monitoring, particularly in cases with minimal acute lung rejection susceptible to rapid progression to severe rejection.