Folate-Induced Remission in Aplastic Anemia with Familial Defect of Cellular Folate Uptake

Abstract

Severe aplastic anemia developed in a young man with an extensive family history of leukemia, pancytopenia, and neutropenia. Megaloblastic changes became evident, and treatment with high doses of folic acid resulted in striking clinical improvement. However, red-cell folate levels remained persistently low despite high serum folate levels. A defect in cellular folate uptake was suspected, and, indeed, uptake of 5–¹⁴CH₃-H₄-folate by stimulated lymphocytes and by bone-marrow cells from the patient was significantly reduced (P14CH₃-H₄-folate by mature red cells, folate utilization in the conversion of deoxyuridylate to thymidylate and polyglutamate formation were all normal. At least five other family members manifest decreased uptake of 5–14CH3–H4-folate by stimulated lymphocytes. These studies suggest that a genetically induced abnormality of folate uptake contributed to this patient's severe, but reversible, aplasia. (N Engl J Med 298:469–475, 1978)