Expression of cytotoxic mediators (perforin, granzyme B, FAS, and FAS-l) in renal allograft biopsies

Abstract

Objectives: To analyze the in situ expression of perforin, granzymeB, FAS-L and FAS in renal allograft biopsies by means ofimmunohistochemistry and correlate these findings with the degreeof histologic rejection and allograft outcome. Methods: Ninety-sixallograft biopsies were divided into three groups: acute rejection (n= 56), chronic rejection (n = 31), and cases with stable renal function(no rejection; n = 9). The expression of perforin, granzyme B, FAS-L,and FAS was evaluated by immunohistochemistry. Results: Asignificantly higher expression of perforin and granzyme B wasobserved in acute rejection biopsies (4.83 ± 0.65 and 30.05 ± 7.93cells/mm2) compared to chronic rejection biopsies (0.71 ± 0.13 and11.4 ± 3.84 cells/mm2; p < 0.001, and p <0.05, respectively), but thiswas not the case for FAS-L (24.44 ± 5.56 in acute rejection versus 18.87± 6.83 in chronic rejection). Perforin, granzyme B, and FAS-L expressionwas significantly higher in the acute rejection group compared to the norejection and control groups. FAS expression was similar in all groups. Amodest correlation between perforin expression and the severity of ARwas observed (r = 0.28, p = 0.05). Perforin was the most reliable markerfor acute rejection diagnosis, with 80% sensitivity and 84.3% specificity.Conclusion: The in situ expression of perforin, granzyme B, and FAS-Lin AR reflects the presence of an active cytotoxic process. Additionalallograft biopsies are necessary in order to evaluate the usefulness ofthese markers for allograft rejection monitoring.

Keywords

• Kidney transplantation/immunology
• Kidney/pathology
• Immunohistochemistry
• Antigens
• CD95
• Graft rejection