Evanston, IL - (NBC) - When Don Coyne shops at the Jewel-Osco grocery store in Evanston, IL, he always looks for Myra De La Vega's smiling face at the cash register.
Coyne, a social worker at Pershing East Magnet School, says De La Vega is always smiling.
"I have a choice, but I always choose her line to go through," explains Coyne.
For more than a decade, Coyne has handed his cash to De La Vega, who greets everyone with a smile. But now, it's Coyne who's giving something to De La Vega, his kidney.
De La Vega was diagnosed with kidney failure four years ago. She's been on dialysis treatment eight hours a day for the last 18 months.
"I'm always thinking and thinking, but I can't get up because my body is so weak," De La Vega said.
She needs a kidney transplant, but none of her family members were a match, but Coyne was and agreed to donate his kidney.
"We've been given too many kidneys," he said.
"It gives me chills, just to see that he would do this just because of his generosity," De La Vega said.
"Our human body can get by with one-third of one kidney and still function normally. I'm confident I'm supposed to do this. I think I'm more fearful when I'm on Lake Shore Drive in the winter time and some of those pot holes try to swallow my car," said Coyne.
The principal at Pershing East Magnet School declared it "Dan Coyne Day." Students learned about De La Vega's story and how kidney transplants work. They also made get well cards to send to sick kids at La Rabida Children's Hospital.
"If you don't give, then you won't get any good things back, and you always need good things in your life," third grader Taylor Stalling said.
The pair will undergo the surgery at Northwestern Memorial Hospital on Friday.