The presence of multiple prothrombotic risk factors is associated with a higher risk of thrombosis in individuals with anticardiolipin antibodies.
OBJECTIVE
To explore the effect of multiple prothrombotic risk factors in individuals with anticardiolipin antibodies (aCL), we evaluated immunologic, coagulation, and genetic prothrombotic abnormalities in a cohort of individuals with different aCL titers.


METHODS
We recruited 87 individuals into 4 categories (normal, low, intermediate, or high) based on their baseline IgG aCL (aCL-IgG) titers. We measured at followup: repeat aCL-IgG, IgM aCL (aCL-IgM), antibodies to beta2-glycoprotein I (anti-beta2-GPI), lupus anticoagulant (LAC) antibodies, protein C, protein S, activated protein C resistance, factor V506 Leiden mutation, methyl tetrahydrofolate reductase (MTHFR) C677T genotype, and prothrombin 20210A gene mutation. Thrombotic events were confirmed.


RESULTS
At recruitment, 20 individuals were negative for aCL-IgG and 67 were positive (22 low, 20 intermediate, and 25 high titer). Twenty of the 87 participants had experienced a previous thrombotic event: 4 in the aCL-IgG negative group and 16 in the aCL-IgG positive group. Among the 87 individuals, the number of those with concomitant prothrombotic risk factors was as follows: 5 had no other prothrombotic risk factors, 32 had 1 risk factor, 24 had 2 risk factors, 10 had 3 risk factors, 10 had 4 risk factors, and 6 had 5 risk factors. Thrombotic events were observed in 20%, 13%, 33%, 10%, 30%, and 50% of these groups, respectively, and the odds ratio associated with a previous thrombotic event was 1.46 per each additional prothrombotic risk factor (95% confidence interval: 1.003-2.134).


CONCLUSIONS
In individuals with positive aCL-IgG, we observed an association between the number of prothrombotic risk factors and history of thrombotic events.
Hudson
Marie
M
Division of Rheumatology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada.
Herr
Andrée-Laure
AL
Rauch
Joyce
J
Neville
Carolyn
C
Chang
Erika
E
Ibrahim
Reda
R
Séguin
Chantal
C
Kassis
Jeannine
J
Busque
Lambert
L
Fortin
Paul R
PR
D000328:Adult; D017153:Antibodies, Anticardiolipin / Q000378:metabolism*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003710:Demography; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology*
D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G