MOLECULAR EXECUTORS OF CELL DEATH-DIFFERENTIAL INTRARENAL EXPRESSION OF Fas LIGAND, Fas, GRANZYME B, AND PERFORIN DURING ACUTE AND/OR CHRONIC REJECTION OF HUMAN RENAL ALLOGRAFTS1,2

Abstract

Two distinct cytolytic pathways have been characterized: one in which the interaction between the Fas antigen and its ligand results in apoptosis, and another in which the pore forming protein perforin and the serine protease granzyme B contribute to DNA fragmentation and cell death. We investigated intrarenal expression of these molecular executors of cell death in light of the potential participation of cytolytically active cellular elements in the antiallograft repertory. Reverse transcriptase-polymerase chain reaction was used to identify intrarenal expression of Fas antigen, Fas ligand, granzyme B and perforin in eighty human renal allograft biopsies; mRNA display was correlated with the Banff histological diagnosis of renal allografts. Our studies demonstrate that: (1) intrarenal expression of Fas ligand mRNA and of granzyme B mRNA are correlates of acute but not chronic rejection; (2) Fas ligand mRNA is not detectable in allografts in the absence of rejection; (3) intrarenal coexpression of members of each lytic pathway (Fas ligand and Fas, granzyme B, and perforin) and that of both pathways (e.g., Fas ligand and granzyme B) are correlates of acute rejection; and (4) a direct correlation exists between the histological severity of acute rejection and intrarenal coexpression of mRNA encoding Fas ligand, Fas, granzyme B, and perforin. Our studies identify, for the first time, the differential expression of the two major lytic pathways in acute and chronic allograft rejection and suggest that specific therapy directed at the cytotoxic attack molecules might be efficacious in the prevention and/or treatment of acute rejection.

Repuncturing the Renal Biopsy

“…Further correlations found included the Th1/Th2 chemokine expression profiles with the clinical outcomes in glomerulonephritis (47,48), the angiotensin-converting enzyme (ACE) expression with the ACE-genotype of the patients (49), and the renin mRNA levels with the medical therapy by ACE inhibition (50). In renal transplants, mRNA expression of inflammatory mediators has been shown to correlate with acute rejection (51)(52)(53). A comprehensive study examining the expression of 15 immuneactivated genes was able to identify acute rejection with high sensitivity and specificity in a population of 60 renal allografts (54).…”

Potential Impact of Microarray Diagnosis of T Cell–Mediated Rejection in Kidney Transplants: The INTERCOM Study

“…While many investigators have analyzed molecular changes in biopsies with histologic rejection, using either RT-PCR (17,18) or microarrays (19)(20)(21), these studies failed to distinguish TCMR from antibody-mediated rejection (ABMR), in part because the criteria for diagnosing ABMR, particularly C4d-negative ABMR, are evolving and remain controversial (22,23). Because of this, we established the Alberta Transplant Applied Genomics Centre (ATAGC) Reference Standard histology system (http://atagc.med.ualberta.ca/) in a prospective cohort of 403 indication biopsies (the BFC403 cohort).…”

Elevation of Cytotoxic Lymphocyte Gene Expression Is Predictive of Islet Allograft Rejection in Nonhuman Primates

“…We have observed that postprandial glucose (PPG) increased 2-3 days before fasting blood glucose (FBG) levels in nonhuman primate islet allograft recipients undergoing rejection; however, unless antirejection therapy is initiated within 1-3 days of the elevation in PPG, it is difficult to rescue significant islet mass (3,4). Activation of transcription of the cytotoxic lymphocyte (CL) genes granzyme B (GB), perforin, and fas ligand (FasL) in transplanted tissue has been reported to be intimately associated with acute renal allograft rejection in humans, particularly when two of the three genes are simultaneously upregulated (5,6). Recently, the elevation of CL gene (ECLG) expression in peripheral blood leukocytes (PBLs) has been correlated with human renal allograft rejection (7,8); however, no studies have been reported that analyze the potential utility of monitoring these markers to predict rejection before the onset of clinical symptoms.…”

“…T-cell-dependent immune activation genes (CL) have been implicated as active participants in the process of acute rejection (5,6). GB and perforin are both involved in the apoptotic pathway of DNA fragmentation and cell death (9,10).…”