I. M. NILSSON, M.D., F.A.C.P. (Corr.); U. HEDNER, M.D.; G. BJÖRLIN, M.D.
Two patients with severe hemophilia B complicated by inhibitors of factor IX (equivalent to 0.6 and 4 to 12 units per millilitre plasma, respectively) are described. Administration of factor IX concentrate alone caused a tenfold increase of the inhibitor, which did not return to its original level for 8 months. Combined treatment, with a large single dose of factor IX concentrate (4000 to 15 000 units of factor IX) and cyclophosphamide, for tooth extractions and severe bleeding episodes, resulted in a prompt decline in antibody titer. Satisfactory hemostasis and suppression of antibody formation required administration of factor IX in doses large enough to neutralize the inhibitor and raise the factor IX level to at least 50% of normal. The inhibitor level remained at zero for 12 days to 3 months, after which it gradually rose to its original level.
NILSSON IM, HEDNER U, BJÖRLIN G. Suppression of Factor IX Antibody in Hemophilia B by Factor IX and Cyclophosphamide. Ann Intern Med. 1973;78:91–95. doi: 10.7326/0003-4819-78-1-91
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Published: Ann Intern Med. 1973;78(1):91-95.
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