In a subgroup analysis of IBD patients compared to healthy controls, significantly reduced sVNT and S-IgG levels were detected in patients on immunosuppressive therapy with anti-TNF agents (sVNT: 2.4% (0–43%) vs. 79% (57–85%), p < 0.001; S-IgG: 142 AU/mL (0–340 AU/mL) vs. 1017 AU/mL (618–1584 AU/mL), p = 0.025) and anti-TNF + azathioprine (sVNT: 0% (0–0%) vs. 79% (57–85%), p < 0.001; S-IgG: 98 AU/mL (98–98 AU/mL) vs. 1017 AU/mL (618–1584 AU/mL), p = 0.009). Here, TNF is linked to inflammatory bowel disease.