Independent association of anti-β2-glycoprotein I antibodies with macrovascular disease and mortality in scleroderma patients

Objective Systemic sclerosis (SSc; scleroderma) is characterized by a unique widespread vascular involvement that can lead to severe digital ischemia, pulmonary arterial hypertension (PAH), or other organ dysfunction. Microthrombotic events and procoagulation factors such as anti–β2-glycoprotein I (anti-β2GPI) or anticardiolipin antibodies (aCL) may be implicated in the development of these manifestations. This study was undertaken to investigate whether anti-β2GPI and aCL are correlated with macrovascular disease, including ischemic digital loss and PAH, in SSc patients. Methods Seventy-five SSc patients with a history of ischemic digital loss and 75 matched SSc controls were evaluated. Anticentromere antibodies (ACAs), anti-β2GPI, and aCL were measured, and clinical associations were determined using conditional and simple logistic regression models. Results Positivity for anti-β2GPI was significantly more frequent in SSc patients with digital loss than in patients without digital loss (P = 0.017), with the IgA isotype of anti-β2GPI showing the strongest association (odds ratio [OR] 4.0). There was no significant difference in aCL frequency between patients with digital loss and control patients. After adjustment for demographic characteristics, disease type, smoking, and ACA, anti-β2GPI positivity was significantly associated with active digital ischemia (OR 9.4), echocardiographically evident PAH (OR 4.8), and mortality (OR 2.9). ACA positivity was associated with history of digital loss (OR 3.28), but not with PAH or mortality. History of digital loss was strongly associated with increased mortality (OR 12.5). Conclusion Anti-β2GPI is significantly associated with macrovascular disease in SSc and independently predicts mortality. It is unclear whether it has a pathogenetic role or simply reveals the presence of underlying endothelial injury. The use of anti-β2GPI as a biomarker of vascular disease in SSc should be further explored.