Detecting an Old Killer

Historically, sickle-cell anemia has been an unheralded killer. It does not occur in dramatic epidemics. Its victims in the U.S. are mostly blacks, and they generally receive less medical attention than whites. The malady affects the red blood cells, which normally are spherical. When the anemia victim is under any stress that reduces the oxygen supply in his blood, his red cells elongate into firm gel-like crescents ("sickles") that block narrow capillaries and deprive tissues of vital oxygen.

The cause of the disease is a gene mutation that occurred centuries ago in Africa. The estimated 2,000,000 Americans who carry one defective gene usually show no symptoms of the disease. The one child in 500 who inherits a sickle-cell gene from each parent has barely an even chance of seeing his 20th birthday and, if he does survive into middle age, is likely to be crippled.

Sickle-cell anemia cannot be cured, though treatment can sometimes control its effects. It can be almost completely prevented, provided that partners who both carry the trait avoid having children. The missing element has been a simple test that would allow carriers to be identified and warned. Now this crucial procedure has been perfected.

Freezing Blood. At a recent meeting of the American Association of Blood Banks in Chicago, Dr. Paul Wolf of Stanford University and Dr. Robert Nalbandian of Blodgett Memorial Hospital in Grand Rapids, announced their success after three years of experiments. They emphasized that they had built on the pioneering studies of Makio Murayama of the National Institutes of Health. Murayama observed that abnormal cells, which carry sickle-producing hemoglobin S, gel at normal body temperature when oxygen content is reduced, then return to normal at 32DEG F.

Working in cooperation with other researchers, Wolf and Nalbandian discovered chemicals that would react to hemoglobin S and other less harmful sickling substances, making a quick screening test possible. A small blood sample is dropped into a tube containing a solution of potassium phosphate, sodium dithionite and saponin. Clouding of the solution is a danger signal but does not specifically identify hemoglobin S. If the first round arouses suspicion, a second test, also based on Murayama's work, is performed immediately. Urea, a natural waste substance produced by the normal liver, breaks some molecular bonds in abnormal hemoglobin. When urea is added to the solution that had shown a positive reaction initially, the liquid clears quickly if hemoglobin S is present.

Neglected Ailment. The Wolf-Nalbandian tests do not distinguish between those who merely carry the sickle-cell trait and those actually affected by the disease. But they do provide a fast, inexpensive method of finding individuals who should get further attention. In an experimental program at Fort Knox, Ky., doctors tested 7,000 black soldiers, 94 of whom were found to carry hemoglobin S. Two of these soldiers actually had sickle-cell anemia.

The announcement of the new tests is opportune. Sickle-cell anemia has long been one of the nation's most neglected diseases. Limited understanding of the disease has been one factor. Another reason, some believe, is racial. Says Wolf: "If it had been a white disease, there would have been money for research, and if the money had been there, the interest would have been there."

Now the situation is improving. A black-led group in New York City recently held a four-and-a-half hour telethon to attract attention and raise money for research. The Federal Government provided $1,000,000 for sickle-cell research last year; this year it appropriated $6,000,000 for further study and genetic counseling.

This file is automatically generated by a robot program, so reader's discretion is required.