Rituximab treatment induces the expression of genes involved in healing processes in the rheumatoid arthritis synovium
Gutierrez-Roelens, I × Galant, C Theate, I Lories, Rik Durez, P Nzeusseu-Toukap, A Van den Eynde, B Houssiau, Fa Lauwerys, Br #
John Wiley & Sons
Arthritis and Rheumatism vol:63 issue:5 pages:1246-1254
OBJECTIVE: Rituximab displays therapeutic benefits in the treatment of rheumatoid arthritis (RA) patients resistant to TNF blockade. However, the precise role of B cells in the pathogenesis of RA is still unknown. In this study we investigated the global molecular effects of rituximab in synovial biopsies obtained from anti-TNF resistant RA patients before and after administration of the drug. METHODS: Paired synovial biopsies were obtained from the affected knee of anti-TNF resistant RA patients before (T0) and 12 weeks after initiation of rituximab therapy (T12). Total RNA was extracted, labeled according to standard Affymetrix procedures and hybridized on GeneChip HGU133 Plus 2.0 slides. Immunohistochemistry and quantitative real-time PCR experiments were performed to confirm the differential expression of selected transcripts. RESULTS: According to paired Student's t-tests, 549 out of 54,675 investigated probe sets were differentially expressed between T0 and T12. Pathway analysis revealed that genes down-regulated between T0 and T12 were significantly enriched in immunoglobulin genes, and genes involved in chemotaxis, leucocyte activation and immune responses (Gene Ontology annotations). By contrast, genes up-regulated between T0 and T12 were significantly enriched in transcripts involved in cell development (Gene Ontology annotation) and wound healing (GSEA). At baseline, higher synovial expression of immunoglobulin genes was associated with response to therapy. CONCLUSION: Rituximab displays unique effects on global gene expression profiles in synovial tissue of RA patients. These observations open new perspectives in the understanding of the biological effects of the drug and in the selection of patients likely to benefit from this therapy.