Tumor Necrosis Factor-α in Serum of Patients with Inflammatory Bowel Disease as Measured by a Highly Sensitive Immuno-PCR

Background: The significance of serum concentrations of tumor necrosis factor-α (TNF-α) in the pathogenesis of inflammatory bowel disease (IBD) is uncertain. We measured TNF-α in serum from IBD patients by immuno-PCR to analyze the relationship between TNF-α and pathophysiologic state in IBD. Methods: Serum samples were collected from 54 healthy blood donors, 29 patients with ulcerative colitis (UC; 46 samples), and 7 patients with Crohn disease (CD; 8 samples). DNA label was generated by PCR amplification using biotinylated primer and was bound with streptavidin to biotinylated third antibody. TNF-α sandwiched by antibodies was detected by PCR amplification of the DNA label. Results: TNF-α could be measured in all samples. The median serum concentration in IBD patients overall was ∼390-fold higher than in healthy donors (median increase, 380-fold for UC, 640-fold for CD). The median serum TNF-α concentration was 1.7-fold higher in the active stage of UC than in the inactive stage (P <0.05), and this difference could be detected in individual patients. Conclusions: Sensitive measurement of serum TNF-α could provide an important pathophysiologic marker for the presence and activity of IBD.