Previously, the supernatant of F. prausnitzii, a highly abundant, butyrate-producing and anti-inflammatory bacterium in the healthy human intestinal mucosa and depleted in IBD patients (Sokol et al., 2008; Lopez-Siles et al., 2016; James et al., 2020), was found not to induce IL-8 secretion by Caco-2 cells, and on the other hand, to reduce IL-8 release from IL-1β-induced Caco-2 cells (Sokol et al., 2008). The gene discussed is IL1B; the disease is irritable bowel syndrome.