Expression of serum MicroRNAs is dysregulated during acute graft versus host disease

Introduction MicroRNAs are expressed in body fluids and have recently been associated with the etiology of acute graft versus host disease (GvHD), but global expression profiling in a haematopoietic stem cell transplant (HSCT) setting is lacking. An improved understanding of the molecular pathogenesis of aGvHD may allow for improved therapeutic options, or guide personalised prophylactic protocols. Methods Mature microRNA serum expression (n=799) was assessed using nCounter technology (NanoString) in a training cohort of diagnostic aGvHD samples (n=12). Analysis assessed for microRNAs that were dysregulated in patients who developed aGvHD compared to no aGvHD. Signature microRNAs were validated in an independent cohort of serum samples taken at aGvHD diagnosis (n=42) and prior to disease onset (day 14 (D14) post-HSCT, n=47). Results NanoString profiling identified 61 microRNAs that were differentially expressed at aGvHD onset, of which n=27 were downregulated (fold change (FC) - 6.94 - - 1.75; p MicroRNA expression was also assessed at D14 post-HSCT in an independent cohort (n=47) to investigate their prognostic marker potential. MiR-146a (p=0.01), miR-20a (p=0.03), miR-18a (p=0.03), miR-19a (p=0.03), miR-19b (p=0.02) and miR-451 (p=0.01) were expressed at significantly higher levels in patients who developed aGvHD vs. no aGvHD. In ROC analysis, miR-146a (A=0.68, p=0.03), miR-19b (A=0.70, p=0.02) and miR-451 (A=0.69, p=0.03) had diagnostic ability with regards to aGvHD incidence, whilst miR-18a (A=0.65, p=0.09), miR-19a (A=0.65, p=0.08) and miR-20a (A=0.67, p=0.06) were approaching significance. Conclusions Circulating microRNAs have the capacity to act as prognostic and diagnostic biomarkers for aGvHD and might assist in developing personalised therapeutic approaches. Their dysregulated expression suggests a role in aGvHD pathology, which warrants further investigation. Disclosures No relevant conflicts of interest to declare.