BackgroundThe antiphospholipid syndrome (APS) is defined by simultaneous presence of vascular clinical events and antiphospholipid antibodies (aPL). The aPL considered as diagnostics are lupus anticoagulant and antibodies anticardiolipin (aCL) and anti-ß2 glycoprotein-I (aB2GP1). During recent years, IgA aB2GP1 antibodies have been associated with thrombotic events both in patients positive, and mainly negative for other aPL, however its value as a pro-thrombotic risk-factor in asymptomatic patients has not been well defined.ObjectiveTo test the role of IgA anti B2GP1 as a risk factor for the development of APS-events (thrombosis or pregnancy morbidity) in asymptomatic population with a 5-year follow-up.Methods244 patients isolated positive for anti-beta2-glycoprotein I IgA (Group-1 study) and 221 negative patients (Group-2 control) were studied. All the patients were negative for IgG and IgM aCL.ResultsDuring the follow-up, 45 patients (9.7%) had APS-events, 38 positive for IgA-aB2GP1 and 7 negative (15.6% vs 3.2%, p<0.001).The incidence rate of APS-events was 3.1% per year in IgA-aB2GP1 positive patients and 0.6% per year in the control group. Arterial thrombosis were the most frequent APS-events (N = 25, 55%) and were mainly observed in Group-1 patients (21 vs 4, p = 0.001). Multivariate analysis were shown as independent risk-factors for the development of APS-events, age, sex (men) and presence of IgA-aB2GP1 (odds ratio 5.25, 95% CI 2.24 to 12.32).ConclusionThe presence of IgA-aB2GP1 in people with no history of APS-events is the main independent risk factor for the development of these types of events, mainly arterial thrombosis.

In conclusion, pretransplant IgA-aB2GP1 was the main risk factor for graft thrombosis and early graft loss. Further research should be made on whether anticoagulation in antibody-positive patients could ameliorate this catastrophic complication.

IgA anti-beta2-glycoprotein I (IgA-aB2GPI) antibodies are currently not included as a laboratory criterion of antiphospholipid syndrome (APS). In the 13th International Congress on Antiphospholipid Antibodies, Galveston, TX, (USA) in 2010, these antibodies were accepted as an APS laboratory criterion in patients who had clinical manifestations of APS but were negative for "consensus" antiphospholipid antibodies (aPL) (IgG and IgM isotypes). Consequently, individuals with thrombotic events who are negative for consensus aPL may be undiagnosed for APS. The most recent publications have confirmed that IgA-aB2GPI antibodies are a risk factor for thrombotic events. In this viewpoint, we propose that IgA-aB2GPI antibodies should be included as an APS consensus criterion and that we have to help Cinderella become a princess.