Identification of a novel biomarker gene set with sensitivity and specificity for distinguishing between allograft rejection and tolerance

Abstract

Here we examined whether the expression of a novel immunoregulatory gene set could be used to predict outcomes in murine models of rapamycin-induced cardiac tolerance, spontaneous hepatic tolerance, and cardiac rejection. The expression of the immunoregulatory gene set was assessed with the GeXP multiplex reverse-transcription polymerase chain reaction (RT-PCR) analysis system, and it was correlated to the pathological and biochemical parameters of the allografts. In rejecting cardiac grafts, the increased expression of an inflammatory set of genes, which included CD45, CD4, CD25, suppressor of cytokine signaling 2, cytotoxic T lymphocyte-associated protein 4 (CTLA4), selectin lymphocyte, interferon-c (IFN-c), programmed cell death 1 (Pdcd1), and granzyme B (Gzmb), was seen 8 days after transplantation along with histological evidence of severe allograft rejection. In tolerant cardiac allografts, the expression of fibrinogen-like protein 2 (Fgl2), Pdcd1, killer cell lectin-like receptor G1 (Klrg1), CTLA4, and lymphocyte-activation gene 3 was associated with tolerance. In a model of liver allograft tolerance, the increased expression of lectin galactose-binding soluble 1, Fgl2, CD39, phosphodiesterase 3B, Klrg1, forkhead box P3 (Foxp3), and transforming growth factor b as well as the inflammatory set of genes was observed 8 to 14 days after transplantation (ie, when there was severe inflammatory injury). At a later time when the liver allografts had been fully accepted and were histologically normal, the expression of the inflammatory set of genes returned to the baseline, but the expression of the tolerogenic set of genes was still increased. Genes that were expressed in tolerant cardiac and liver allografts included Fgl2, Klrg1, and Foxp3, whereas genes associated with rejection included CD25, Additional Supporting Information may be found in the online version of this article.Abbreviations: CTLA4, cytotoxic T lymphocyte-associated protein 4; Ebi3, Epstein-Barr virus induced 3; Fgl2, fibrinogen-like protein 2; Foxp3, forkhead box P3; GITR, glucocorticoid-induced tumor necrosis factor-related protein; GOT, glutamate oxaloacetate transaminase; Gpr83, G protein-coupled receptor 83; GPT, glutamate pyruvate transaminase; Gzmb, granzyme B; IFN-c, interferon-c; Klrg1, killer cell lectin-like receptor G1; Lgals1, lectin galactose-binding soluble 1; mRNA, messenger RNA; MST, mean survival time; Nrp1, neuropilin 1; Nt5e, 5 0 -nucleotidase ecto; OLT, orthotopic liver transplantation; PCR, polymerase chain reaction; Pdcd1, programmed cell death 1; Pde3b, phosphodiesterase 3B; POD, postoperative day; qRT-PCR, quantitative reverse-transcription polymerase chain reaction; RT-PCR, reverse-transcription polymerase chain reaction; Sell, selectin lymphocyte; Socs2, suppressor of cytokine signaling 2; TGF-b, transforming growth factor b; Treg, regulatory T cell.

Fibrinogen-Like Protein 2/Fibroleukin Induces Long-Term Allograft Survival in a Rat Model through Regulatory B Cells

“…In transplantation, administration of soluble FGL2 was shown to double skin allograft survival but did not result in long-term survival [12]. Recently, FGL2 together with Foxp3 and killer cell lectin-like receptor G1, were shown to be over-expressed in models of liver and cardiac transplantation tolerance [29]. Mice deficient in FGL2 develop autoimmune glomerulonephritis [28].…”

Spontaneous Resolution of Acute Rejection and Tolerance Induction With IL-2 Fusion Protein in Vascularized Composite Allotransplantation

“…To determine if there was a sustained difference in the cellular regulatory levels between ALS þ CsA and ALS þ CsA þ hIL-2/Fc treated recipients, we examined the gene expression profile of various effector and regulatory markers using real-time PCR at day 35 posttransplantation, 2 weeks after cessation of the treatment, as these biomarkers have been shown to correlate with rejection versus tolerance induction (33). A striking difference was demonstrated in the relative expression of FoxP3 when compared to effector cell gene markers between the ALS þ CsA and ALS þ CsA þ hIL-2/Fc treated groups (Figure 4b).…”

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“…The administration of EPA to CBA mice transplanted with B10 hearts exhibited a permanent survival ( Figure 1). As previously reported, 12 the cardiac allografts exhibited moderate to severe rejection on day 8 after transplant as assessed according to a standard cardiac biopsy grading system. Additionally, the cardiac allografts treated with EPA on day 100 after transplant did not display any signs of rejection.…”