~33% of patients have too many anti-pig antibodies to qualify

Approximately one third of patients on the organ transplant waitlist have preformed anti-pig antibodies at levels high enough that today's genetically modified pig kidneys would be rejected almost immediately via hyperacute rejection. These patients cannot benefit from xenotransplantation at all with current technology. This matters because the entire promise of xenotransplantation is to eliminate the organ shortage that kills 17 Americans per day, but if a third of the waitlist is excluded from the start, the technology fails the patients who are most desperate. The problem is compounded by the fact that there is no established threshold for what level of preformed anti-pig antibodies is safe: clinicians have no validated cutoff to tell a patient 'you qualify' or 'you don't.' The reason this persists structurally is that humans develop anti-pig antibodies through dietary exposure to pork, gut bacteria cross-reactivity, and prior blood transfusions, and there is no desensitization protocol proven to durably reduce these antibodies to safe levels before a xenotransplant.