Washington (CNN) -- A 31-year-old Oklahoma woman helped make medical history and started a chain of "paying it forward" when she decided to donate her kidney to a stranger halfway around the world, a man in Athens, Greece, officials announced Friday.
Elizabeth Gay was the history-making donor, and Michalis Helmis was the recipient. His wife, Dora Papaioannou-Helmis, in return donated one of her kidneys to a patient in Wilkes-Barre, Pennsylvania.
The announcement of the first intercontinental organ exchange was made at a news conference held at the Greek Embassy in Washington.
"The joint effort of 'paying it forward' confirms what a huge difference an individual can make," Greek Ambassador Vassilis Kaskarelis said during the press conference. It "confirms that we are all part of one world, that our fates are intertwined and that if we all work together, the possibilities are endless"
So far, one Greek and four American lives have been saved, and two more transplants are scheduled with a donor from Trinidad and Tobago joining the chain.
Gay was the first in the chain of kidney transplants.
"The opportunity to help change someone's life, in itself, would be an honor but to potentially change the world -- it's huge," she said, "I felt that ... a month of surgery and recovery in order to help give someone else life was completely worth it."
Before Gay could get the opportunity, though, Greek law had to be changed to allow the exchange.
Greece's transplant law -- intended to prevent black market organ harvesting -- stated that only a first or second relative could donate a kidney. Papaioannou-Helmis, whose husband was in desperate need of a kidney transplant, spearheaded the efforts to change the law.
After meeting with various officials and ministers, Helmis family attorney Vasilis Athanasiou said they "understood what could be done."
The law was changed 18 months later, and the Greek couple flew to the United States in December 2011 so the husband could start the process and receive his new kidney. Four months later, she returned to donate her kidney to a Pennsylvania man -- a chain started by a practice called "kidney pair donation."
"Kidney pair donation is when two people come together -- someone loves somebody enough that they want to give them a kidney, but they find out that they're not compatible," said Dr. Michael Rees, director of transplantation at the University of Toledo, where the Gray/Helmis kidney exchange took place. "So instead, they're willing to give a stranger a kidney so that another stranger can give their loved one a kidney."
"As a donor I feel very well and I'm very calm," Papaioannou-Helmis, who attended Friday's news conference with her husband via Skype, said through a translator. "Every day that I see Michalis well I'm very happy. And every day I think of Liz, and I think of the person that received my kidney, Mr. Charles Ripple and I wonder how he's doing, how he's feeling every day."
"It's just been fabulous. Everything is working good," Ripple responded, "I feel the best I've felt in a couple years."
Theodora, Dora Papaioannou-Helmis' full name, in Greek means "gift from God."