Three of the donors had offered to give loved ones a kidney before, but weren't the right match. The fourth donor was a Good Samaritan.

"The best untold story is that one of the donors is an anonymous donor," said Dr. Sandra Cockfield, medical director of the renal transplant program at the University of Alberta.

"So this is an individual who came forward to donate not to someone they actually know on the waiting list, but had heard about the long waiting lists and the difficulty of living on dialysis," and came forward to donate to a stranger.

In this surgical marathon, the Good Samaritan or "non-directed donor" came forward and was matched to a recipient, allowing the chain of paired exchanges or domino surgeries to take place. The Good Samaritan was thus able to facilitate four transplants, including the last to someone on the waiting list.

Правда, при этом вставал еще вопрос о запрете живого неродственного донорства в РФ...

From the National Organ Transplant Act of 1984, as amended:
Title 42 - The Public Health and Welfare
Chapter 6A - Public Health Services
Subchapter II - General Powers and Duties
Part H - Organ Transplants
Sec. 274e. Prohibition of organ purchases
(a) Prohibition
It shall be unlawful for any person to knowingly acquire, receive, or otherwise transfer any human organ for valuable consideration for use in human transplantation if the transfer affects interstate commerce.

(b) Penalties
Any person who violates subsection (a) of this section shall be fined not more than $50,000 or imprisoned not more than five years, or both.

© Definitions
For purposes of subsection (a) of this section:

(1) The term "human organ" means the human (including fetal) kidney, liver, heart, lung, pancreas, bone marrow, cornea, eye, bone, and skin or any subpart thereof and any other human organ (or any subpart thereof, including that derived from a fetus) specified by the Secretary of Health and Human Services by regulation.

(2) The term "valuable consideration" does not include the reasonable payments associated with the removal, transportation, implantation, processing, preservation, quality control, and storage of a human organ or the expenses of travel, housing, and lost wages incurred by the donor of a human organ in connection with the donation of the organ.

(3) The term "interstate commerce" has the meaning prescribed for it by section 321(b) of title 21.

Поэтому буду очень благодаран, если переведешь.