TNF-α and soluble forms of TNF receptors 1 and 2 in the serum of patients with Crohn's disease and ulcerative colitis.

INTRODUCTION Soluble forms of tumor necrosis factor (TNF) membrane receptors 1 and 2 (sTNFR1 and sTNFR2) are present in body fluids. Their higher concentrations are observed in a number of diseases, including inflammatory bowel diseases (IBDs). sTNFR1 and sTNFR2 are capable of binding TNF-α, acting as an inhibitor that competes with a membrane receptor. The results of the available studies on sTNFR1 and sTNFR2 concentrations in IBDs and their association with disease activity are ambiguous. OBJECTIVES The aim of the study was to assess sTNFR1 and sTNFR2 concentrations and their correlation with disease activity in patients with IBD. PATIENTS AND METHODS Plasma levels of TNF-α, sTNFR1, and sTNFR2 were measured in 55 consecutive patients with ulcerative colitis (UC), 50 subjects with Crohn's disease (CD), and 41 healthy controls. We assessed the associations of those markers with other inflammatory markers, disease activity and location, type of treatment, and complications. RESULTS Positive correlations were observed between CD activity and sTNFR1 and sTNFR2 levels (r = 0.42 for both, P <0.01) as well as between UC activity and sTNFR1 and sTNFR2 levels (r = 0.63, P <0.0001; r = 0.47, P <0.001; respectively). TNF-α levels correlated only with CD activity (r = 0.29, P <0.05). In patients with nonactive UC, higher sTNFR2 levels were observed compared with controls. In patients with CD, higher TNF-α and sTNFR2 levels were demonstrated in patients who developed complications. CONCLUSIONS sTNFR1 and sTNFR2 are more sensitive inflammatory markers than TNF-α in the assessment of disease activity in patients with CD and UC. Higher sTNFR2 levels are observed in patients with CD and complications.