Tumor necrosis factor-alpha in serum of patients with inflammatory bowel disease as measured by a highly sensitive immuno-PCR.

The significance of serum concentrations of tumor necrosis factor-alpha (TNF-alpha) in the pathogenesis of inflammatory bowel disease (IBD) is uncertain. We measured TNF-alpha in serum from IBD patients by immuno-PCR to analyze the relationship between TNF-alpha and pathophysiologic state in IBD. 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-alpha sandwiched by antibodies was detected by PCR amplification of the DNA label. TNF-alpha could be measured in all samples. The median serum concentration in IBD patients overall was approximately 390-fold higher than in healthy donors (median increase, 380-fold for UC, 640-fold for CD). The median serum TNF-alpha 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. Sensitive measurement of serum TNF-alpha could provide an important pathophysiologic marker for the presence and activity of IBD.