Testing of individual taxa for the change upon anti-TNF administration revealed no shifts in JIA, but identified several taxa changing in CD: Alistipes [class Bacteroidia] decreased in abundance after therapy with anti-TNF, whereas Intestinibacter, Flavonifractor, and Ruminococcus [all class Clostridia] increased. The gene discussed is TNF; the disease is juvenile idiopathic arthritis.