A US preschool teacher has told the BBC of her delight in being able to save a five-year-old pupil's life by providing the child with one of her kidneys.
Beth Battista said that she had no hesitation in offering her kidney after hearing of Lyla's protracted search to find a suitable donor.
"I knew I just had to get tested rather than watch her suffer," she said.
Both Beth and Lyla are now recovering after the successful transplant operation last Wednesday.
The teacher and mother-of-two said that she heard about Lyla's condition after her mother Dena Carreyn shared a Facebook post about the girl's desperate need for a living kidney donor.
Lyla was diagnosed a year ago with microscopic polyangiitis (MPA), a rare autoimmune disorder which requires 12 hours of dialysis a day.
Beth contacted the the UW Health Transplant Program in Wisconsin and, after two tests in July and August, was deemed to be a suitable donor for Lyla.
It was a rare match because she needed to be the right blood group with few antibodies picked up from previous bouts of sickness. She also needed to have matching antigens.
In September she discovered that the child was to be a pupil in her class at the Kids' Express Learning Centre in Madison.
The operation itself required surgeons to make four small incisions in her abdomen in order to pull the kidney out, before taking it to Lyla, who was in a nearby hospital ward.
"It was the same level of a pain as having a caesarean," the teacher told the BBC, "but I'm pleased to say that as soon as the kidney was put inside Lyla it began working immediately."
"I was discharged from hospital 48 hours after the surgery and am feeling OK although really tired.
"But I am told this common among donors because their remaining kidney needs to grow to make up for the missing organ.
"I'm really proud to have saved her life."
Her actions have won widespread plaudits on social media.
"You are an inspiration for all of us to go out there and be a donor," one commentator on Facebook said.