As Sister Thomas Welder weighs the situation she is in right now, what she sees most strongly is a moment that is a "perfect teacher."

"It teaches me to be grateful," she said Friday from her office at the University of Mary in Bismarck.

Her gratitude extends far and wide - to the family friend, a 45-year-old woman, who donated a kidney to her in 2001, to the support of her community of Benedictine sisters, and to the "amazing goodness" of people who have already called Mayo Clinic in Rochester, Minn., asking to be tested to see if they may be a match for a second kidney donation.

Sister Thomas, president of the University of Mary since 1978, learned recently that her donated kidney is failing because of what is called the BK polyomavirus. Sister Thomas has a condition called polycystic kidney disease.

She said researchers now speculate that what has been viewed as kidney rejection in the past may have been this virus, which remains mostly dormant in the general population, but can emerge in people with aggressive immune system suppression, which includes transplant recipients.

Sister Thomas' medical team hopes to maintain her in reasonably good health without going on dialysis, she said, until such time as she may find another kidney donor.

The first donated kidney was an incredible gift, she said, which gave her a new lease on life.

In fact, the donor told her that, "If I gave you one good day, it was worth it." The transplanted kidney is still serving her, she said; her medical team has lowered her anti-rejection regime to decrease the burden of the virus on the kidney.

Sister Thomas said she continues to work full time, and is thankful for that.

"It's great to wake up in the morning and have something to do that is larger than oneself," she said.

The goodness and generosity of people has been amazing and overwhelming through this, Sister Thomas said. "It's very humbling.

"It's a real call to trust in God's love above all else," she said.

Mayo Clinic's process is confidential, she said, but her staff has inferred from what they've been told that quite a number of people have called and asked to be screened to see if they are a match to donate to her and that screening, initially by blood type, will begin soon.

"It's overwhelming," she said, that people are so willing to give her a part of themselves.