Investigating circulating MicroRNA expression in systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disorder, which is caused by the loss of immune tolerance, resulting in the production of autoantibodies directed against several self-antigens in the body. MicroRNAs (miRNAs) are a class of small noncoding RNA molecules that are involved in regulation of post-transcriptional gene expression and play an important role in immune regulation and autoimmunity. Circulating miRNAs have recently emerged as potential biomarker candidates for various human conditions, including autoimmune diseases. The primary objective of this study was to utilize a comprehensive plasma miRNA profiling data from an SLE case-control discovery sample to identify a candidate set of highly SLE-relevant circulating miRNAs to be further evaluated in large follow-up studies. The miRNA profiling data were produced using the miScript Human miRBase Profiler HC series of PCR arrays that contained 2402 human miRNA qPCR assays. A total of 280 plasma miRNAs showed >2-fold expression difference between SLE cases and controls, of which 66 showed >25 fold down-regulation in SLE patients as compared to SLE-free controls. Of those 280 plasma miRNAs, 178 exhibited significant down-regulation (P