As expected,24 patients with FMF and healthy controls secreted IL-1β and IL-18 equally in response to Clostridium difficile toxin A (TcdA) alone, but contrary to patients with FMF, the cytokine ratios for healthy donors were low because of inhibition of wild-type Pyrin by colchicine (figure 1A). This evidence concerns the gene MEFV and familial Mediterranean fever.