Gene expression of monocytes from rheumatoid arthritis patients treated with bDMARDs and methotrexate.

It is well documented that patients affected by rheumatoid arthritis (RA) have distinct susceptibility to the different biologic Disease-Modifying AntiRheumatic Drugs (bDMARDs) available on the market, probably because of the many facets of the disease. Monocytes are deeply involved in the pathogenesis of RA and we therefore evaluated and compared the transcriptomic profile of monocytes isolated from patients on treatment with methotrexate alone or in combination with tocilizumab, anti-TNFalpha or abatacept, and from healthy donors. Differential expression analysis of whole-genome transcriptomics yielded a list of regulated genes suitable for functional annotation enrichment analysis. Specifically, abatacept, tocilizumab and anti-TNFalpha cohorts were separately compared with methotrexate using a rank-product-based statistical approach, leading to the identification of 78, 6, and 436 differentially expressed genes, respectively. Gene expression profiling was performed on primary monocyte cultures from a total of 31 samples, according to the following experimental design: 10 samples from healthy patients, 6 samples from MTX-, 5 samples from abatacept-, 5 samples from anti-TNFalpha-, and 5 samples from tocilizumab-treated patients.