BACKGROUND: Cardiac allograft rejection (AR) can cause graft dysfunction and even mortality, and an early noninvasive diagnosis of cardiac AR is required. This study aims to identify candidate biomarkers in peripheral blood for cardiac AR, which might benefit early diagnosis.

MATERIAL AND METHODS: Gene expression profile (ID: GSE5967) of peripheral blood from cardiac allograft recipients was achieved from the Gene Expression Omnibus database, including 7 chips in rejection group, 7 chips in post-rejection group, and 7 chips in control group. After data preprocessing, limma package was used to screen the differentially expressed genes (DEGs) between these groups (|log2 fold change| ≥0.58, and p-value <0.05). Then, online software DAVID was utilized to study the pathways and functions involving these DEGs (p-value <0.05).

RESULTS: Totally, 21 up-regulated and 16 down-regulated DEGs were identified between rejection and control groups, and up-regulated DEGs were mainly enriched in bio-functions about translation and ribosome. Furthermore, 3 up-regulated and 14 down-regulated DEGs were identified between post-rejection and control groups. The down-regulated DEGs in 2 contrast groups were mainly enriched in bio-functions about lipid biosynthesis and membrane.

CONCLUSIONS: RPL7, RPL11, RPS23, RPS25, SCD5, CSF3R, and FPR1 were predicted as candidate biomarkers in peripheral blood for monitoring cardiac AR. The up-regulation of RPL7, RPS25, RPS23, and RPL11 might promote the translation of AR-related cytokines, and the down-regulation of SCD5, CSF3R, and FPR1 might reduce the stability of cell membrane, mediating cytokines secretion and the phagocytosis of macrophages. However, further studies are required to validate these predictions.

Keywords: Biological Markers, Cardiology, Heart Transplantation