Joe's mother Sheriden said he was still enjoying life

Joe Cawse, of Maidstone, was diagnosed with a rare form of leukaemia and given two years to live in March 2005.

His two brothers are not a match while a search of a worldwide database of 10m potential donors also drew a blank.

The Anthony Nolan Trust was holding a new session on Thursday at Joe's school, West Borough Primary.

Joe's father, Phil, lost his brother to leukaemia in 1979, when the bone marrow register was in its infancy.

Enjoying life

Joe has a form of the disease which affects less than 1% of all children with leukaemia.

His mother, Sheriden, said so far Joe was healthy and enjoying life at the school in Greenway.

"He is doing OK, we have been lucky," she said. "He just takes time off to go to the Royal Marsden Hospital in Surrey."

More than 350 potential donors have so far come forward at clinics held in Maidstone, Gillingham and Faversham but none have been a match.

'Complete stranger'

"There must be someone out there who is a match," said Mrs Cawse.

Debby Jepps, spokeswoman for the Anthony Nolan Trust, said: "Joe is now dependent on a complete stranger coming forward and providing the life-saving match he needs.

"The most recent search on the worldwide register of over 10m donors was unsuccessful."

The trust said that donors on its register must be willing to donate stem cells to any patient they match.

They should be between 18 and 40, in good health, weigh more than 8st (50kg) but not be severely overweight.