The presence of RA was associated with significantly altered expression for 6 of the 23 genes (P<.05 for all, not adjusted for multiple comparisons): S100 calcium binding protein A12, interleukin-18 receptor accessory protein, caspase 5, S100 calcium binding protein A8, aquaporin 9, and cluster of differentiation 79b.
Expression of IL-18 receptor alpha and beta chains (IL-18R alpha and IL-18R beta, respectively), interferon-gamma (IFN gamma), and IL-17 messenger RNA (mRNA) by peripheral blood mononuclear cells, by total RA synovium cells containing T cells obtained after collagenase digestion, and by RA fibroblast-like synoviocytes was determined by reverse transcription-polymerase chain reaction.