Anti-endothelial cell antibodies do not correlate with disease activity in systemic sclerosis

Introduction
Anti-endothelial cell antibodies (AECA) recognize endothelial cell proteins and are thought to play an important role in vascular damage observed in systemic scleroderma (SSc) and many other autoimmune diseases. In SSc, AECA were found to be more common in patients with pulmonary hypertension, digital ulcers and nailfold capillaroscopic changes. Until now, there have been no studies examining the association between AECA positivity with the activity and duration of the disease.

Aim
To evaluate associations between the presence of AECA in sera of patients with SSc and internal organs involvement as well as disease activity.

Material and methods
Sera of 58 patients with SSc (50 with localized subtype and 8 with diffuse subtype) were examined for AECA presence using an indirect immunofluorescence technique. Several clinical and laboratory features were also evaluated as well as disease activity and disease duration.

Results
A significant association between positive AECA and a subtype of SSc (p = 0.021) was found, as well as between presence of digital ulcers and digital scars (p = 0.001), calcinosis (p = 0.02), acroosteolysis (p = 0.028) and a nearly significant association between AECA and lung fibrosis (p = 0.47). No association between disease duration, disease activity and AECA (p = 1.000 and 0.191, respectively) was present.

Conclusions
Anti-endothelial cell antibodies are not associated with the activity of SSc. Digital ulcers, calcinosis and acroosteolysis are more common among AECA-positive patients suggesting that the presence of AECA might be an indicator of vascular complications development in SSc. Positive AECA among patients with lung fibrosis indicate their possible role in the development of lung disease. Further prospective studies including a greater number of patients are required.