The Machine Answered

Every year, some 10,000 ailing babies are born in the U.S. to parents with hostile blood types caused by the mysterious Rh factor./- Even with the most modern treatment, the best that doctors could hope for in such cases was to hold the death rate down to 20%. Last week, after listening to a pessimistic summary of these facts, doctors at the American Academy of Pediatrics convention in San Francisco heard some unexpected good news. Dr. Louis K. Diamond of Boston Children's Hospital rose from the audience and said quietly: "I would be remiss if I did not report some new developments."

The 80% Chance. All that is known about the Rh factor has been learned since 1940, when it was found to occur in the blood of 85% of white people, more than 90% of Negroes. It causes trouble after Rh-positive blood (containing the factor) gets into the bloodstream of an Rh-negative woman (whose blood lacks the factor). This may happen either by transfusion or in carrying the child of an Rh-positive father. The woman's Rh-negative blood then develops antibodies to destroy the alien Rh factor. She may transmit these antibodies to her infant's Rh-positive blood, where they attack the red cells and cause acute anemia (erythroblastosis fetalis). In modern practice there is an 80% chance of saving the infant's life promptly after birth, through a dramatic operation: the baby's blood is drained from its body and replaced with Rh-negative blood.

Dr. Diamond and his colleagues had long wondered why so many mixed-blood babies are ever born alive. "Theoretically, most of them should have been destroyed in the uterus, but this rarely happened. There must be something in the mother's blood," he reasoned, "which protected her baby until it was born."

The Startling Fact. To track down this mysterious something, Dr. Diamond and associates decided to check on all the blood used in 179 replacement transfusions. Each donor's sex, age, and other data were marked by punches on business machine cards. Then the cards were run through a tabulating machine. From the machine came a startling fact: of 137 infants with erythroblastosis who got the Rh-negative blood of male donors, 27 died; of 42 who got women's blood, not one died.

The inference was so obvious that Dr. Diamond and his colleagues have not dared to use a man's blood since. Of 45 later cases given the blood of female donors, only one was lost, and that child was almost dead at birth. Other children's hospitals have switched to female donors for this type of exchange transfusion and are building up higher columns of hopeful figures. Dr. Diamond, though he still has no idea what the protective substance in a woman's blood may be, is looking for ways to use it in other children's diseases.

Mixing blood with different Rh characteristics may have harmful after-effects extending far beyond infant anemia, the University of Pennsylvania announced this week. Trying to get at the cause of hearing defects in 50 children suffering from a type of cerebral palsy, researchers in the Audiology Section found that every one of the afflicted children was the product of a mixed Rh ancestry. Now the researchers are checking on other hearing defects, not connected with cerebral palsy, to see whether Rh incompatibility is also the villain.

/- So called because it was first found in the blood of rhesus monkeys.

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