Factor XII autoantibodies as a novel marker for thrombosis and adverse obstetric history in patients with systemic lupus erythematosus.
OBJECTIVE
To investigate the clinical significance of anti-factor XII (FXII) in a large cohort of patients with systemic lupus erythematosus (SLE).


METHODS
This study comprised 127 patients with SLE. IgG and IgM anti-FXII were tested by an in-house ELISA. 123 healthy donors comprised the control group.


RESULTS
51 (40%) patients with SLE and 9 (7%) healthy controls were positive for anti-FXII. IgG and IgM anti-FXII were frequently found in patients with thrombosis (28% and 13%, respectively). Levels of IgG and IgM anti-FXII were higher in patients with thrombosis than in the control group (p<0.001 and p=0.005, respectively). Anti-FXII was more frequent in patients with arterial thrombosis (31% vs 4% for IgG and 14% vs 3% for IgM, respectively) and venous thrombosis than in controls (37% vs 4% for IgG). IgG anti-FXII were more frequent in patients with miscarriages and fetal death (35% and 40% vs 4% for IgM). The prevalence of IgM anti-FXII was not different between groups.


CONCLUSIONS
Anti-FXII are frequent in patients with SLE. Their presence is associated with thrombosis and adverse obstetric history, making these antibodies a novel marker for the antiphospholipid syndrome.
Bertolaccini
Maria Laura
ML
Lupus Research Unit, The Rayne Institute, King's College London School of Medicine at Guy's, King's and St Thomas' Hospitals, London SE1 7EH, UK. maria.bertolaccini@kcl.ac.uk
Mepani
Kirti
K
Sanna
Giovanni
G
Hughes
Graham R V
GR
Khamashta
Munther A
MA
D000022:Abortion, Spontaneous / Q000209:etiology / Q000276:immunology; D000328:Adult; D016736:Antiphospholipid Syndrome / Q000175:diagnosis* / Q000209:etiology; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005174:Factor XII / Q000276:immunology*; D005260:Female; D005313:Fetal Death / Q000209:etiology / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D016682:Lupus Coagulation Inhibitor / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D013927:Thrombosis / Q000209:etiology / Q000276:immunology
D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016682:Lupus Coagulation Inhibitor; D005174:Factor XII