Pretreatment magnitude of gene sets derived from the synovial myeloid phenotype and classically activated monocytes correlates with clinical response to anti-TNFα (infliximab) therapy. Analysis of synovial tissue microarray data from 62 rheumatoid arthritis patients in GSE21537 prior to initiation of infliximab (anti-TNFα therapy). Scores for gene sets for phenotypes, defined from the Michigan cohort training data, as well as gene sets derived from purified immune cell lineages (see Methods), were calculated from the GSE21537 data and compared against anti-TNFα clinical outcome at 16 weeks as defined by European League Against Rheumatism (EULAR) response criteria as assigned in GSE21537. Scores versus EULAR response are plotted for the synovial myeloid phenotype (A), lymphoid phenotype (B), fibroid phenotype (C), as well as classically activated M1 monocytes (D), B cells (E) and T cells (F). Statistical significance for good compared with poor EULAR response for the level of each gene-set module was calculated based upon the t-statistic (* = P ≤0.05, **P ≤0.01).