Lindsay Porter's kidneys weighed 16 pounds before her transplant.

STORY HIGHLIGHTS

(CNN) -- By the time Lindsay Porter had her kidneys removed two years ago, they were bulging -- covered in cysts -- and together weighed 16 pounds.

Her abdominal area was so distended, "I looked nine months pregnant, and people regularly asked when I was due," Porter said.

As she prepared for a transplant to address her polycystic kidney disease, Porter, 47, had mixed feelings -- relief to have found a donor, tinged with resignation. She was looking forward to both a new kidney, and a lifetime on immune system-suppressing drugs.

"You get this brand new shiny kidney, and then they give you drugs that eventually destroy it," said Porter.

But that scenario may eventually change, if results of a new pilot study are replicated in a larger group of patients. The study, published Wednesday in the journal Science Translational Medicine, describes eight kidney transplant patients, including Porter, who received a stem cell therapy that allowed donor and recipient immune cells to coexist in the same body.

The effect, in a handful of those patients, was to trick the recipient's immune system into recognizing the donated kidney as its own.

When it works, patients become a sort of medical rarity called a chimera.

"Chimerism is a condition wherein two different genetic cell populations are present in the body, and both cell types are tolerated," said Dr. Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest Baptist Medical Center, who was not involved in the study, via e-mail.

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Transplant without lifetime of drugs?