miRNA differential expression in Rheumatoid arthritis(RA) blood: Microarray analysis of miRNAs in blood from RA and healthy donors. Overall design: Total RNA was extracted from blood samples from 8 RA patients and 8 healthy donors and pooled for miRNA microarray analysis. RNA quality control, labeling, hybridization, and scanning were performed by LC Sciences (Houston, TX) using the latest probe content in the Sanger miRBase (Sanger miRBase 11.0). Preliminary statistical analysis was performed by LC sciences on raw data normalized by the locally weighted regression method on the background-subtracted data.