human body, effectively robbing the injected individual of any 4400 powers and in addition making this person allergic to promicin. The identity and makeup of this substance is not stated, and the only known source of it so far is from the future. A second method also exists for removing promicin from non-4400 humans, through the promicin-neutralizing ability of Jordan Collier. There also appears to be a substance that can counteract the anti-promicin's effects as Tom Baldwin, during his time as a member of the "Marked", uses this substance to help Isabelle Tyler regain her powers by removing her promicin allergy. Like the anti-promicin, this substance appears to be from the future. As discovered by Marco in the episode "The Starzl Mutation", Seattle Presbyterian Hospital started using a flawed radiation machine to treat their cancer patients in 1969. The microswitches that controlled the machine were not functioning properly, so the doses were incorrect. This went on for just under five years. Once the hospital figured out what they were doing they tested everyone who had ever been exposed to it and in some cases the radiation induced a small mutation. This mutation was a slight alteration of the eleventh chromosome, named the "Starzl mutation" after the manufacturer of the faulty machine. The mutation is hereditary, meaning people that got it passed it onto their children. The Starzl mutation is both harmless and conserved in those offspring; they live normal healthy lives. While the offspring of a returnee normally do not retain the ability to generate promicin, a second-hand report from John Shaffner (an ex-special ops soldier) suggested that the offspring of a 4400 and a Starzl mutant will be "promicin-positive", meaning they will have abilities. This is believed by Tom Baldwin and Diana Skouris to be the reason why the abductees were returned to the Seattle area – it is the only place they are likely to encounter individuals who possess the Starzl mutation and therefore the only place they are likely to produce children with 4400 abilities. The promicin-inhibitor "piggybacks on glucose", after entering the brain through facilitated diffusion. It is a binding protein; that is, it binds itself to promicin in the body and neutralizes it. However, if there is no promicin for it to bind to, it remains in the body. Eventually, it builds up to toxic levels in the lymph nodes, damaging the immune system. The