RESUMO
<p><b>OBJECTIVE</b>To investigate the expression of perforin and granzyme B in rejection response following liver transplantation, and evaluate their roles to be used as predictive markers of rejection.</p><p><b>METHODS</b>The expression of perforin and granzyme B in liver biopsies obtained from liver allograft recipients was determined by immunohistochemistry. Biopsies were classified into two groups-no evidence of rejection and rejection-according to Histopathologic criteria. The relationship between the perforin/granzume B expression and acute rejection was analyzed.</p><p><b>RESULTS</b>From 19 patients, thirty-five liver biopsies were obtained after liver transplantation. Among them, nineteen samples were diagnosed as rejection response. The frequencies of perforin and granzyme B expression in rejection group were 100% (19/19) and 94.7% (18/19), respectively. While those in no rejection group were 25.0% (4/16) and 12.5 (2/16), respectively. In most rejected samples, perforin and granzyme B were expressed simultaneously. Only three samples showed perforin expression alone, while no samples demonstrated granzyme B expression alone. There was a close relationship between perforin/granzyme B expression and liver allograft rejection.</p><p><b>CONCLUSION</b>Perforin and granzyme B expression seemed to be related to the development of acute rejection following liver transplantation, and might be served as sensitive and reliable markers in diagnosing acute rejection in early stage.</p>