The stem cells donated by a Chinese man have been transplanted into a 16-year-old Indian boy suffering from leukemia.

Vimarsh Raina, a medical expert in New Delhi who helped with the operation, says the Indian teenager is in stable condition.

The donor, 37-year-old volunteer of China Marrow Donor Program, says he never expected to save a foreigner when he joined the CMDP in 2012.

"It's unexpected to have my bone marrow samples matched with a foreign person. It's a gift for my life. As the father of a 12-year-old child, I understand the feelings of the Indian boy's parents. I just want to help."

The transplant took place on Saturday morning, shortly after the stem cells arrived in India from China.

The chance of two non-relatives having stem cells matched can be less than one in tens of thousands.