title: Acquired inhibitors of factor V.
abstract: The clinical and laboratory data on the 12 patients with an acquired inhibitor to factor V have been reviewed. The degree of clinical bleeding in these patients varied from none to severe, and in most patients the inhibitor was transient. The combination of a markedly prolonged partial thromboplastin time and Quick prothrombin time and failure of normal plasma to correct these tests, in the presence of a normal thrombin and prothrombin and proconvertin time, seems to be pathognomonic for a factor V inhibitor. The inhibitors have physicochemical properties of immunoglobulins and a few have been characterized as polyclonal IgG antibodies or a mixture of IgM and IgG antibodies. The etiology and pathophysiologic mechanism of their development is unknown, but there seems to be a close relationship to major surgery. When tested with inhibitor plasma, the plasmas from 9 patients with hereditary factor V deficiency from 7 unrelated families did not contain factor V antibody-neutralizing material.
mesh_terms: D000328:Adult; D000368:Aged; D000906:Antibodies; D001780:Blood Coagulation Tests; D001792:Blood Platelets; D002648:Child; D002850:Chromatography, Gel; D004592:Electrophoresis, Starch Gel; D005165:Factor V / Q000037:antagonists & inhibitors* / Q000276:immunology; D005260:Female; D006801:Humans; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008297:Male; D009500:Neutralization Tests; D013917:Thrombin / Q000494:pharmacology
chemical_list: D000906:Antibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D005165:Factor V; D013917:Thrombin