The gene expression profile in the synovium as a predictor of the clinical response to infliximab treatment in rheumatoid arthritis

• Published in: PloS one Vol. 5; no. 6; p. e11310
• Main Authors: Lindberg, Johan, Wijbrandts, Carla A, van Baarsen, Lisa G, Nader, Gustavo, Klareskog, Lars, Catrina, Anca, Thurlings, Rogier, Vervoordeldonk, Margriet, Lundeberg, Joakim, Tak, Paul P
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 25.06.2010; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Aggregates; Antibodies, Monoclonal - therapeutic use; Antirheumatic Agents - therapeutic use; Arthritis; Arthritis, Rheumatoid - drug therapy; Arthritis, Rheumatoid - genetics; Arthroscopy; Biologi; Biology; Biomarkers; Biopsy; Breast cancer; Cancer therapies; Cell division; DNA microarrays; Drug therapy; Female; Gene expression; Gene Expression Profiling; Genes; Genetic research; Genetics and Genomics/Gene Expression; Hospitals; Humans; Immunohistochemistry; Immunology; Immunology/Autoimmunity; Immunology/Immune Response; Immunotherapy; Infliximab; Lymphocytes; Male; Mathematical models; Medical research; Medicin och hälsovetenskap; Medicine; Metabolism; Middle Aged; Monoclonal antibodies; NATURAL SCIENCES; NATURVETENSKAP; Nucleic Acid Hybridization; Oligonucleotide Array Sequence Analysis; Oligonucleotides; Patients; Precision medicine; Protein expression; Rheumatoid arthritis; Rheumatoid factor; Rheumatology; Ribonucleic acid; RNA; Statistical analysis; Statistical methods; Synovial Membrane - metabolism; Synovial Membrane - pathology; Synovium; Transcription; Tumor necrosis factor; Tumor necrosis factor-TNF; Tumor necrosis factor-α
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0011310

Although the use of TNF inhibitors has fundamentally changed the way rheumatoid arthritis (RA) is treated, not all patients respond well. It is desirable to facilitate the identification of responding and non-responding patients prior to treatment, not only to avoid unnecessary treatment but also for financial reasons. In this work we have investigated the transcriptional profile of synovial tissue sampled from RA patients before anti-TNF treatment with the aim to identify biomarkers predictive of response. Synovial tissue samples were obtained by arthroscopy from 62 RA patients before the initiation of infliximab treatment. RNA was extracted and gene expression profiling was performed using an in-house spotted long oligonucleotide array covering 17972 unique genes. Tissue sections were also analyzed by immunohistochemistry to evaluate cell infiltrates. Response to infliximab treatment was assessed according to the EULAR response criteria. The presence of lymphocyte aggregates dominated the expression profiles and a significant overrepresentation of lymphocyte aggregates in good responding patients confounded the analyses. A statistical model was set up to control for the effect of aggregates, but no differences could be identified between responders and non-responders. Subsequently, the patients were split into lymphocyte aggregate positive- and negative patients. No statistically significant differences could be identified except for 38 transcripts associated with differences between good- and non-responders in aggregate positive patients. A profile was identified in these genes that indicated a higher level of metabolism in good responding patients, which indirectly can be connected to increased inflammation. It is pivotal to account for the presence of lymphoid aggregates when studying gene expression patterns in rheumatoid synovial tissue. In spite of our original hypothesis, the data do not support the notion that microarray analysis of whole synovial biopsy specimens can be used in the context of personalized medicine to identify non-responders to anti-TNF therapy before the initiation of treatment.