Blood not so simple.Red cells made in a laboratory have been infused into people.Until the 1940s, blood transfusions often went wrong because some of the main blood-group systems, such as the Rhesus factor, had yet to be discovered.This hit or miss approach to matching donors with recipients is now a thing of the past, as tests for all sorts of characteristics of an individual's blood have become available.But finding a well-matched donor can still be difficult.Some patients have blood types so rare that there may be but a handful of appropriate donors in the country where they live.On November 7th a consortium of researchers at several British institutions, co-ordinated by NHS Blood and Transplant, a government health authority, and Bristol University, announced a step towards solving this problem.They have successfully transfused into two healthy volunteers red blood cells grown from appropriate stem cells donated by others.Until now, such manufactured red cells had been given only to those whose own stem cells had been the source.The stem cells used for this experiment, however, were extracted from blood donated in the normal way.The researchers mixed into this donated blood magnetic beads armed with proteins that stick specifically to the stem cells in question, binding them to the bead.
