A pilot study of gene expression-based categorization of pancreas transplant biopsies

Gene expression profiling has emerged as a powerful strategy to define transcriptional mechanism activated in organ transplantation. We performed a pilot feasibility study of mRNA-based pancreas transplant biopsy stratification. The mRNAs expression of 32 genes, observed in renal transplant dysfunction, and 10 pancreas-specific genes were evaluated in 26 pancreas transplant biopsy specimens by quantitative real-time polymerase chain reaction using TaqMan Low Density Array technology. Unsupervised 2D hierarchical clustering segregated the biopsies in two main cluster branches, A and B. Six of seven patients (85.7%) in cluster A and 6 of 19 (31.6%) in cluster B retained functioning pancreas allograft. CD20/MS4A1 mRNA and protein, in addition to CD 3 protein, were detected in four specimens in cluster B. Three of those four pancreas transplants were subsequently lost. Our study demonstrates the potential association of gene expression with clinical outcome of pancreas transplants and justifies further studies in an independent cohort.