Application of a new immunohistology scoring system (IH score): analysis of TNF-α in synovium related to disease activity score in infliximab-treated patients with rheumatoid arthritis.

ABSTRACT

OBJECTIVES: This study aimed to analyze the relationship between the expression of tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6) in synovium and the disease activity score (DAS) 28 (C-reactive protein, CRP) in treatment of infliximab for rheumatoid arthritis (RA). METHODS: Synovial tissues were obtained from 16 infliximab-treated patients and assessed for TNF-α and IL-6 with a new immunohistology (IH) scoring system. The validation of IH score was performed and applied for the analysis of correlation between synovial TNF-α or IL-6 and DAS28 (CRP) in addition to Rooney score. RESULTS: The IH score had high internal validity; the IH score of TNF-α strongly correlated with serum CRP and matrix metalloprotease-3 (MMP-3), as well as DAS28 (CRP) and the Rooney score. IL-6 did not correlate with DAS28 (CRP). CONCLUSIONS: This study indicates that the IH score is useful as a new procedure to assess the cytokine expression easily and TNF-α in synovium correlates with disease activity in patients with RA treated with infliximab.