Tailor made kidneys grown for transplant could become a reality with the discovery by British scientists, announced today, that bone marrow cells are able to turn into kidney cells.

Even before the huge challenge of growing an entire kidney in the lab is realised, the discovery brings closer the prospect of cultivating small amounts of kidney cells to repair a damaged kidney.

"This discovery is very exciting and means we have new ways to treat kidney damage caused by cancer or other diseases," said Nick Wright, head of the Imperial Cancer Research Fund's histopathology unit and one of the scientists involved in the research.

About 100,000 people in the UK suffer from some form of kidney disease; about a third receive regular treatment; and about one-sixth have had a kidney transplant. There are more than 5,000 people on the waiting list for a transplant.

Sir Paul Nurse, director general of the ICRF, said: "Ultimately, this research may one day lead to regenerating a new kidney using the patient's own stem cells. The potential for therapies is enormous and very exciting."

ICRF researchers were studying bone marrow stem cells, a type of naturally-occuring cell which later develops and divides to become regular blood cells. Last year, the same scientific team found that these cells could turn into liver cells.

One of the biggest problems with transplants, and with the idea of growing spare organs in "organ farms", is rejection - the body's immune system attacks the transplanted organ as alien.

If it became possible to culture cells or grow organs using a patients' own cells, the rejection problem would disappear.