RA patients exhibit aberrant expression of miR-146a, miR-155, miR-132 and miR-16 versus healthy controls. (a) RNA was isolated from healthy control individuals (n = 9), disease control individuals (n = 4), and RA patient (n = 17). PBMCs and relative expression levels of miR-146a, miR-155, miR-132, miR-16, and miRNA let-7a were analyzed by qRT-PCR using U44 RNA as an internal control. Average is indicated by bars. *P < 0.05, **P < 0.01, as determined by one-way analysis of variance. For RA patients, closed circles indicate patients undergoing anti-TNF-α therapy at time of sample collection, squares indicate MTX treatment, and open circles indicate other or no treatment. (b) Disease activity was determined for patients using CRP and ESR values and correlated with miRNA expression. Normal CRP and ESR values were classified as inactive disease (n = 3; patients 9, 12, and 14 in Table 1), and higher than normal CRP or ESR values were classified as active disease (n = 8; patients 1a, 1b, 2, 4, 5, 6, 10, and 15 in Table 1). Those patients with no or incomplete data for CRP/ESR values were omitted. *P < 0.05, as determined by t-test. (c) PBMCs were collected from patient RA-1 before (November 2007) and after (January 2008) MTX treatment and miRNA expression was examined using qRT-PCR. miRNA expression is largely consistent over time, with the exception of increased miR-16 expression. CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; miRNA, microRNA; MTX, methotrexate; PBMC, peripheral blood mononuclear cell; qRT-PCR, quantitative real-time RT-PCR; RA, rheumatoid arthritis; RT-PCR, reverse transcription polymerase chain reaction; TNF, tumor necrosis factor.