OBJECTIVE: To investigate the expression status and clinical significance of cytoprotective proteins to human renal allografts.
METHODS: Expressions of cytoprotective proteins: antiapoptotic protein (A20), hemeoxygenase-1 (HO-1), and B-cell lymphoma/leukemia-X(L) (Bcl-X(L)) were analyzed by immunohistochemistry and compared in 30 renal allografts, including 10 grafts undergoing acute rejection (AR), 10 grafts undergoing chronic rejection (CR), and 10 nonrejecting (NR) grafts.
RESULTS: Expressions of A20, HO-1 and Bcl-X(L) localized mainly in endothelial, smooth muscle, and infiltrating mononuclear cells. A20 expressed in grafts undergoing AR (5.04 +/- 0.71) and CR (3.20 +/- 0.64), not in NR grafts, and its expression in CR was weaker than that in AR ( P < 0.01). HO-1 expressed in AR (7.91 +/- 2.24), not in CR and NR. Bcl-X(L) was detected in all grafts (AR: 10.62 +/- 3.17; CR: 8.50 +/- 2.45; NR: 11.03 +/- 2.77), but had a decreased expression levels in CR.
CONCLUSION: A20 and HO-1 may play protective role for AR, and A20 may be the essential protein having protective function for CR.