Factor XII auto-antibodies present in a patient with a B-cell lymphoma.
A 64-year-old woman was transferred for investigation of a mediastinal mass, biopsy of which showed a diffuse large B-cell lymphoma. She was also found to have an antiphospholipid antibody. The pre-operative coagulation screen showed a prolonged activated partial thromboplastin time, 71.3 s (normal range, 26-36 s), which was not corrected by the addition of normal plasma. The dilute Russell's viper venom time was positive. Anti-cardiolipin assay was strongly positive, immunoglobulin M was 153 AU; immunoglobulin G was normal, 3.1 AU. Assays of factors VIII, IX and XI showed higher concentrations with increasing dilutions in one-stage factor assays from 1: 10 to 1: 80 suggestive of an inhibitor. Factor XII was 9 U/dl and results were unaffected by increasing dilution, suggesting specific antibodies to factor XII. The factor XII antigen was 40 U/dl. The patient had immunoglobulin M auto-antibodies to factor XII.
Davidson
Simon J
SJ
Department of Haematology, Royal Brompton Hospital, London, UK. S.Davidson@rbh.nthames.nhs.uk
Burman
John F
JF
Nicholson
Andrew G
AG
Jones
David W
DW
Dusmet
Michael E
ME
D001323:Autoantibodies / Q000097:blood*; D001780:Blood Coagulation Tests; D005174:Factor XII / Q000276:immunology*; D005260:Female; D006801:Humans; D016393:Lymphoma, B-Cell / Q000276:immunology*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000276:immunology*; D008875:Middle Aged
D001323:Autoantibodies; D005174:Factor XII