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Jerry Spivak
Jerry Spivak has found a molecular defect in polycythemia patients.


Test Confirms a Rare Blood Disease

“A patient has too many red blood cells, causing headaches and potentially fatal blood clots. You want to find out why. That shouldn’t be too hard,” says hematologist Jerry L. Spivak, M.D., “but more often than we’d like, it is.” Spivak says any number of things can elevate RBC levels: smoking, heart disease, taking muscle-building androgens, kidney disease. But perhaps the most elusive cause is an acquired blood disorder—a slow-acting malignancy, really—called polycythemia vera, that occurs in one to five of every 100,000 people. With this disorder, patients not only have more red cells—hematocrits can almost double in some cases—but there’s also a slow, steady buildup of white cells and platelets. Blood volume also increases—a double whammy because that masks the disease from the doctor while putting the patient at a higher risk of blood clots and stroke. Women under the age of 40 are at particular risk for clotting complications.

Now Spivak and Alison Moliterno, a Doris Duke fellow in the Division of Hematology, have found a molecular defect in polycythemia patients that enables their sure diagnosis. “We haven’t had a handle on this disease, something that lets us distinguish it from more treatable problems,” Spivak explains. “Now we do.”

In a recent article in The New England Journal of Medicine, he reported that patients with the disease apparently lack normal receptors for a growth factor called thrombopoietin. (In the tiniest amounts, thrombopoietin somehow insures that the body produces the proper number of mature blood cells.) In a blood test developed by Spivak, polycythemia patients consistently fail to test positive for the normal receptor. Spivak now uses the test routinely to confirm the disease. The test is also helping him dispel the myth that polycythemia is a disease of older adults. “I saw a 15-year-old with it the other day,” he says.

Hopkins is probably the nation’s major center for polycythemia vera. Interestingly, the disease was first identified and described here nearly a century ago by Sir William Osler, Johns Hopkins’ eminent first chief of medicine. Spivak, who’s studied the disease here for two decades, has tailored management on monitoring a patient’s blood volume and keeping it normal. He sees a fair number of patients who’ve suffered from overly aggressive treatment such as chemotherapy, but maintains that keeping a close watch on the blood volume works best. “None of our patients in the last two decades has had a stroke or blood clot.”