Down regulation of protective genes is associated with cellular and antibody-mediated rejection

Despite advances in immunosuppressive therapy, rejection still remains the main obstacle to a successful transplant. This study aims to explore the gene expression profile of the rejection process in order to decrease the number of unnecessary endomyocardial biopsies in stable patients.

A total of 300 formalin-fixed and paraffin-embedded (FFPE) endomyocardial biopsies sampled from 63 heart allograft recipients were included in this study. Acute cellular rejection (ACR) and antibody-mediated rejection (AMR) were diagnosed by histological analysis and immunohistochemical C4d staining, respectively. Analysis of gene expression was performed by quantitative real-time polymerase chain reaction. The samples were grouped according to the ISHLT rejection classification, aiming the statistical analysis.

There was a significant decrease in the HMOX1, AIF1, and CCL2 transcript over the post-transplantation period in non-rejection group (P<.001). Furthermore, the ADIPOR1, ADIPOR2, BCL2L1, and VEGFA protective genes were significantly downregulated in the ACR group (P<.05). ADIPOR2, BCL2L1, IL6, and NOS2 genes were also significantly downregulated in the AMR group than in the non-rejection group (P<.05).

The downregulations of the protective genes contribute to the allograft rejection, and the archived FFPE samples are useful for the gene expression analysis aiming the allograft rejection surveillance.