By Jane Elliott
Health reporter, BBC News
A year ago actor David Harewood got a call that was to change not only his life but that of a complete stranger.
A stranger shares David's DNA
He was told his bone marrow could be a match for a desperately ill person.
Six months on, David - who has starred in Blood Diamond, Babyfather, Fat Friends and The Vice - has heard the unknown recipient is doing well.
He admits he is intrigued to know more about the person who now shares his DNA.
"I got a letter from the Anthony Nolan Trust to say the person was recovering and I did feel really emotional," said David.
"The person is on the mend and I'm glad I was able to help.
"I would love to find out more about the person. I would really love to, but I think there is a period of two years before you can find out, as there is still a risk they could lapse."
David put his name onto the trust's register two years ago after hearing a speech by Beverley De Gale.
She set up the African Caribbean Leukaemia Trust (ACLT) in a desperate attempt to find new black donors and to try and to help her six-year-old son Daniel who needed a bone marrow transplant to save his life.
"I had been on the register for a couple of years, but some people are on the register for 20 years with no calls, so I wasn't expecting to hear from them, but they called and said 'you are a possible match'.
David found harvesting painful, but bearable
David admits the procedure of stem cell harvesting was painful, but said it was not unbearable.
"I had four days of stem cell stimulation, having injections every day.
"A nurse came round and gave injections in my arm to stimulate the amount of stem cells that were produced by my body.
"I went to a hospital in Harley Street and got hooked up to a dialysis machine. I sat there for four hours while the procedure took place.
"I have never had that many needles in my life. I hate needles, but the idea of saving somebody's life just made that pale into comparison, so I just gritted my teeth.
"It was quite uncomfortable but I have had worse pain being kicked across the football pitch or falling off my bike so I would urge people not to think about the discomfort, but about saving somebody's life."
David urged people from ethnic minorities to join the register.
"How would you feel if it was your mother, your father, our daughter who needed help? You would literally comb the earth for a remedy, for something that could save their lives.
"But that could be the person living right next door, and the only reason that they were not on the register was because they did not know.
"It is heartbreaking to think there are people dying everyday through ignorance. I would be clear that anybody who was thinking about it should join the register because they could save somebody's life."
Ethnicity is important
Anne-Margaret Little, of the Anthony Nolan Trust, backed David's call: "It is vital for us to increase the number of young donors from all ethnic groups on our register."
Dr Paul Travis, of the Scottish Centre for Regenerative Medicine agreed.
"Transplants of bone marrow - which is the tissue that makes all of the blood cells - provide a chance for life for many patients with diseases of the blood, usually cancers of the blood cells.
"However a transplant that is not matched to the patient can itself cause disease, and can even result in the death of the patient.
"The best chance for finding a match for a patient is from a donor from the same ethnic background, and the more donors there are, the better the chances for the patient that one will be the perfect match.
"Though individuals from black and ethnic minority communities do volunteer readily to become donors, there is still a severe shortage and patients from ethnic minority groups, and more especially from a mixed race background, face long, uncertain waits.
"Many will die without a donor to give them a chance for life."