Intragraft mRNA expression of cytokines and growth factors in human kidney allograft biopsies by in situ RT-PCR analysis

Chronic Active Antibody-Mediated Rejection Is Associated With the Upregulation of Interstitial But Not Glomerular Transcripts

Molecular assessment of renal allografts has already been suggested in antibody-mediated rejection (ABMR), but little is known about the gene transcript patterns in particular renal compartments. We used laser capture microdissection coupled with quantitative RT-PCR to distinguish the transcript patterns in the glomeruli and tubulointerstitium of kidney allografts in sensitized retransplant recipients at high risk of ABMR. The expressions of 13 genes were quantified in biopsies with acute active ABMR, chronic active ABMR, acute tubular necrosis (ATN), and normal findings. The transcripts were either compartment specific (TGFB1 in the glomeruli and HAVCR1 and IGHG1 in the tubulointerstitium), ABMR specific (GNLY), or follow-up specific (CXCL10 and CX3CR1). The transcriptional profiles of early acute ABMR shared similarities with ATN. The transcripts of CXCL10 and TGFB1 increased in the glomeruli in both acute ABMR and chronic active ABMR. Chronic active ABMR was associated with the upregulation of most genes (SH2D1B, CX3CR1, IGHG1, MS4A1, C5, CD46, and TGFB1) in the tubulointerstitium. In this study, we show distinct gene expression patterns in specific renal compartments reflecting cellular infiltration observed by conventional histology. In comparison with active ABMR, chronic active ABMR is associated with increased transcripts of tubulointerstitial origin.

Cytokine gene expression in kidney allograft biopsies after donor brain death and ischemia-reperfusion injury using in situ reverse-transcription polymerase chain reaction analysis

BACKGROUND

This study focuses on the cytokine genes expression after brain-death, ischemia-reperfusion injury, and during allograft rejection.

METHODS

A total of 49 needle core biopsies from kidney transplant recipients, performed before and during transplantation procedures were studied. The first biopsy was taken during procurement of the organ, the second after cold ischemia, and the third after approximately 30 min of reperfusion. We also assessed 34 allograft biopsies obtained during acute rejection. Tubular and glomerular expression of interferon (IFN)-gamma, transforming growth factor (TGF)-beta1, platelet-desired growth factor-B (PDGF-B), interleukin (IL)-2, IL-6, IL-10 mRNA was analyzed with reverse-transcription polymerase chain reaction (RT-PCR) in situ technique, which allows to detect a few copies of the target gene without destruction of the tissue architecture.

RESULTS

Compared with normal kidney tissue from living donor, high gene expression of IFN-gamma, TGF-beta1, PDGF-B, IL-2, IL-6, and IL-10 was detected in all procurement specimens. After reperfusion gene expressions of IL-2, IL-6, and IL-10 were significantly upregulated in renal tubules compared to biopsies taken after cold ischemia. The gene expression of IFN-gamma, TGF-beta1, and PDGF-B remained stable after organ procurement, during cold ischemia, and after reperfusion. Gene expression of IFN-gamma, IL-2, IL-6, IL-10, and PDGF-B in procurement biopsies, as well as in those taken after cold ischemia and reperfusion, were significantly higher than during the period of acute rejection.

CONCLUSION

The data presented herein strongly point out the importance of the immunological and morphological injury that occurs before and during transplantation. The increase of inflammatory response after brain death is important for further stimulation of the immune response and long-term kidney survival.

The Regulatory/Cytotoxic Graft-Infiltrating T Cells Differentiate Renal Allograft Borderline Change From Acute Rejection

The interpretation of cellular infiltrate from renal transplant recipients with borderline (BL) changes is still a challenging problem. To analyze the immune phenotype of such infiltrate, we quantified the mRNA expression of Foxp3 and interleukinL-10 and granzyme B (GB) in 15 kidney biopsies with BL changes. Controls were patients presenting type IA acute rejection and nonrejecting patients. Only levels of GB mRNA correlated significantly with response to antirejection therapy. Levels of Foxp3 mRNA in BL changes were intermediate between type IA acute rejection and nonrejecting controls. To determine the balance of alloagressive to graft-protecting T cells, we quantified the Foxp3/GB ratio. BL changes T cells infiltrate expressed a significantly higher Foxp3/GB ratio than that in IA acute rejection. These results suggest that T cell infiltrate from BL change exhibit a tolerogenic rather than a cytotoxic phenotype.

Renal allograft biopsies with borderline changes: predictive factors of clinical outcome

The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.