(INSIDE EDITION) - A year ago, little Lyla Carreyn got very sick, very fast. Her parents didn't know what was wrong until doctors diagnosed her with a rare, auto-immune-related disorder that causes kidney failure.
After enduring 10 to 12 hours of dialysis every day for nine months, physicians said the 4-year-old's life depended on getting a new kidney.
A national search was launched over the summer to find a compatible donor, with no luck.
And then mom Dena Carreyn was called into Lyla's Wisconsin school this month to meet her daughter's new preschool teacher. There were a host of issues to discuss with the new hire about Lyla's medical condition and the treatment and medications she needs while at school.
"It's a whole thing," the mother wrote on her Facebook page.
During the sit-down, Carreyn was handed a "gift," which she duly opened, expressing dismay that she had not brought something herself.
Inside was a note:
"I may just be her teacher now, but soon a little piece of me will be with Lyla forever. I'm Lyla's kidney donor."
Carreyn's stunned and weepy reaction was captured on video, which has gone viral, generating hundreds of comments to her Facebook page and 1,000 likes.
The teacher, Beth Battista, was in tears herself, moved beyond words and feeling momentous joy at being able to save a little girl's life.
"Beth Battista is more than our hero; she is our miracle," Carreyn wrote.