For 75 years, the standard tools for autoimmune disease have consisted of steroids, cytotoxics and broad biologics that tamp down the entire immune system. They can help, but they are rarely curative. “They’re blunt instruments,” Regcell Inc. CEO Mike McCullar told BioWorld. “They can’t distinguish good immune cells and bad immune cells,” which is why many carry black-box warnings and must be taken for years, sometimes for life.