Urine immune profiling by measurement of multiple cytokine/chemokine mRNA levels in renal allograft dysfunction

Abstract

Background: An accurate diagnosis of cause of acute renal graft dysfunction is crucial for the optimal management of transplant recipients. Currently available tests are either insensitive or nonspecific, or are invasive, such as allograft biopsy. During last decade, attempts have been made in search of non invasive markers for the evaluation of cause of graft dysfunction. We studied a set of genes expressed on cytotoxic T Lymphocytes and those related to functioning of regulatory or helper T cells. Methods: We obtained 108 urine samples from 108 renal allograft recipients at the time of graft biopsy done for the evaluation of cause of graft dysfunction. RNA was extracted from urinary cells and messenger RNA (mRNA) encoding perforin, granzyme B (GB), FoxP3, CD3?, CXCR3, TGF-?, CTLA4, PI-9, IL-10, TNF?, T-bet and 18SrRNA measured with the use of quantitative real time polymerase chain reaction (RT-PCR). The levels of expression of genes were correlated with the biopsy findings and the results compared among different groups. Renal allograft biopsies at this institution are performed when there is unexplained rise in serum creatinine of >20% from the baseline value and reported according to Banff classification. SPSS v10.0 used for analy-sis.Results: The mRNA copy numbers of GB, Perforin, FoxP3, CD3, CXCR3, TGF-?, CTL A4, PI9, IL-10, TNF?, and T-bet were log transformed and mean (± SD) levels studied. The expression of all studied genes were compared between ‘nonspecific biopsy findings’ and other specific diagnoses. GB, Perforin, FoxP3, TGF-?, CD3?, CTLA4 CXCR3 and T-bet were higher in acute cellular rejection (ACR), whereas, TGF-? was also found higher in infection, and PI-9 in chronic allograft nephropathy (CAN) and borderline rejection group. Conclusion: Measurement of mRNA levels for genes like GB, Perforin, FoxP3, TGF-β, CD3?, CTLA4, CXCR3 and T-bet in urine samples offers a non invasive means of diag-nosing cause of graft dysfunction