The Iowa Supreme Court ruled yesterday that a leukemia victim does not have the right to send a letter to a potential bone marrow donor to plead for a transplant.

The court ruled that such a letter would violate the reluctant donor's privacy.

The Iowa high court's decision was a reversal of an earlier, partial victory for William Head, 27, a leukemia victim. Tim Riley, Head's attorney, told the court that an unfavorable ruling would mean a "death sentence" for his client.

As the court was deliberating on his appeal last week, however, British doctors announced that they had found three potential donors for Head in their computer banks.

Supreme Court administrator Paul Wieck said that development "had no effect at all on the court's decision." He said the justices were probably not even aware of the new donors when they ruled on the case.

Experts in medical ethics have said the case, no matter the outcome, will be a landmark in the ethics of medicine because there are so many patients who need transplanted organs, including kidneys, corneas, lungs, livers and hearts.

They said a decision to allow Head to send the woman a letter could have a "disastrous impact" in other cases.

Head contracted leukemia three years ago, and has not responded to chemotherapy. The disease and the treatments to fight it destroy the body's bone marrow. But in some cases, when a good match of tissue type can be found, transplants can increase survival chances somewhat.

At the University of Iowa hospitals, a computer bank of information on tissue types turned up a "Mrs. X" as the only potential match of tissue for Head. She was the only potential donor recorded among the nation's tissue bank records.

But when the university wrote to "Mrs. X" and asked if she would donate bone marrow she failed to respond. During a follow-up telephone call, she said she would "if it were a family member." The university did not tell her it had a specific candidate waiting.

The university refused to give the woman's name to Head, saying that her right of privacy and the confidentiality of the hospital records must not be compromised.

The lower court had ordered the university to tell the woman the specifics of Head's case so that she could decide whether to help him.

Head's attorney argued that decision was proper because it kept the identity of "Mrs. X" a secret while providing some help for Head.

But the high court ruled that her listing on a tissue-typing register was protected under Iowa law.

"When a person submits to a hospital procedure, the hospital's duty should not depend on whether the procedure is for that person's benefit or the potential benefit of someone else," Justice Mark McCormick wrote in the unanimous opinion.

"A potential donor has a valuable right of privacy . . . . A valuable part of the right of privacy is the right to avoid publicity concerning private facts," the ruling said.