Taken from the San Francisco Chronicle (3/18/02)
Hans Keirstread, a researcher at UC Irvine, plans to see govt approval to test whether embryonic stem cells can repair spinal injuries in paralyzed patients without cloning the cell to overcome immune system rejection. He says that when he recieves permission,he intends to propose using immune-suppression drugs to prevent rejection of the transplanted stem cells. The concern has been that a patients immune system would reject transplanted cells. In theory, by talking the nucleus from a patient's cell and inserting that nucleus into the stem cells, researchers hope to create genetically compatible transplants.
Paralyzed actor Christopher Reeve was wheeled into a senate hearing room to testify in favor of a bill by Sen. Dianne Fienstein. She wants to ban the cloning of babies but to permit so-called therapeutic cloning to advance stem cell studies. "Why do we need therapeutic cloning?" asked Reeve, who told senators that "implantation of human embryonic stem cells is not safe unless they contain the patients own DNA"
Keirstead said scientists could use off-the-shelf medicines to prevent immune system rejection of certain stem cell transplants without therapeutic cloning.
Robert Lanza, chief scientist at Advanced Cell Technology in Mass, an ardent advocate for both embryonicstem cell studies and therapeutic cloning, agreed that in the course of the political debate, the need for cloning to overcome immune system rejected has been overstated, especially in such conditions as paralysis, Parkinson's, MS and other conditions of the CNS. Explaining that the CNS is "immune privileged". This means that brain and nervous tissue have little or no immune system protection and are less likely than other organs to reject transplants.
Lanza says that you couldn't use immune suppression drugs to test stem cell therpies on conditions like diabetes. Weakening the immune system leaves patients open to infection and the negative effects of immune suppression would outweigh the benefits of stem cell therapy for diseases that are not life-threatening of debilitating.
So, while therapeutic cloning is not a prerequisite for all stem cell studies, Lanza said to deny scientists that option "would be like moving ahead with one hand tied behind your back."
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