Anti-Annexin V Antibodies: Association with Vascular Involvement and Disease Outcome in Patients with Systemic Sclerosis

Background: Systemic Sclerosis (SSc) is characterized by skin thickening, fibrosis and vascular obliteration. The onset and course are heterogeneous. Prominent features include autoimmunity, inflammation and vascular damage. Aim of study: To measure the level of serum Anti-Annexin V antibodies in SSc patients and to study its significance in relation to vascular damage in these patients. Patients and methods: Twenty patients with SSc (12 with diffuse SSc and 8 with the limited form) and 10 healthy age and sex matched volunteers as controls were all subjected to routine laboratory testing and immunological profiling including antinuclear, anti-Scl-70, anticentomere, anticardiolipin antibodies and anti-annexin V antibodies titres. Vascular damage was assessed by clinical examination and assessment of the disease activity score, nailfold capillaroscopy and colour flow Doppler of the renal arteries; Doppler echocardiography was used for assessing pulmonary hypertension. Results: Anti-annexin V antibodies were detected in 75% of patients. Comparisons between anti-annexin V in diffuse and limited subgroups showed no significance; however a statistically significant positive correlation was found between Anti-annexin V titre and the degree of vascular damage in SSc patients. Anti-annexin V increased significantly in patients with severe vascular damage in comparison with those less affected (15.3 ± 6.6 vs. 11.25 ± 3.6, P , 0.05). A significant positive correlation was found between Anti-annexin V titre and both the ACL titre (r = 0.79, P , 0.001) and the resistive index of the main renal artery (r = 0.42, P , 0.05). Conclusion: Anti-annexin V antibodies were significantly present in sera of patients with SSc. Patients with more severe forms of vascular damage had higher titres of these antibodies. Anti-annexin V antibodies are a sensitive predictor of vascular damage in SSc and could serve as a useful parameter in discriminating patients with a higher risk of vascular affection from those without.