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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Gailani, D. Search for Related Content PubMed Articles by Gailani, D. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Blood, 15 June 2003, Vol. 101, No. 12, pp. 4649 Factor XI inhibitors Alloantibody inhibitors to factor VIII or factor IX are well-recognized consequences of replacement therapy in hemophilia. Factor replacement is also a mainstay of treatment for factor XI deficiency, but reports of factor XI inhibitors are anecdotal and few are well characterized. Factor XI deficiency is an autosomal disorder common in Ashkenazi Jews, in whom the prevalence of severe (homozygous) disease is 0.1% to 0.3%. Two mutations account for more than 90% of abnormal alleles in this population. Homozygosity for the type II (Glu117Stop) mutation is associated with the absence of factor XI antigen in plasma. This mutation is also found in Iraqi, Middle Eastern, and Sephardic Jews and in Arabs and probably arose in the Middle East at least 2000 years ago. The type III mutation (Phe283Leu) is likely of more recent European origin and is associated with reduced, but detectable, antigen (about 10% of normal in homozygotes). Compound heterozygotes for the 2 mutations have factor levels of about 3%. In this issue, Salomon and colleagues (page 4783) report on inhibitor formation in 118 Israeli patients with severe factor XI deficiency. Seven individuals with histories of plasma infusion had inhibitors. All 7 are homozygous for the type II nonsense mutation. This group represents a striking 33% of all patients with this genotype exposed to plasma. Prospective studies of factor VIII inhibitors in hemophilia A indicate that many are transient, so the actual incidence of inhibitors in factor XI type II homozygotes exposed to plasma may be considerably higher than 33%. Given this, it seems prudent to prospectively identify these patients and, when possible, use alternatives to plasma therapy such as antifibrinolytic agents. Accurately measuring very low factor XI levels with clotting assays is notoriously difficult. This study points out the importance of determining factor XI genotype in Jewish patients to identify those at high risk for developing inhibitors. David Gailani Vanderbilt University CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Prevalence, causes, and characterization of factor XI inhibitors in patients with inherited factor XI deficiency Ophira Salomon, Ariella Zivelin, Tami Livnat, Rima Dardik, Ron Loewenthal, Ophelia Avishai, David M. Steinberg, Michael H. Rosove, Niamh O'Connell, Christine A. Lee, and Uri Seligsohn Blood 2003 101: 4783-4788. [Abstract] [Full Text] [PDF] This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Gailani, D. Search for Related Content PubMed Articles by Gailani, D. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?

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