Background: Anti-endothelial cell antibodies (AECA) are a known biomarker of endothelial dysfunction and damage in clinical practice, especially in autoimmune disease.

Objectives: To determine the relation between natural AECA levels and prognosis related to coronary artery disease.

Methods: Candidates for coronary angiography were prospectively enrolled. AECA levels were determined by ELISA assay. Mortality was evaluated after more than 5 years follow-up.

Results: Of a total 857 patients, 445 had high AECA levels (group 1) and 412 had low levels (< 1 OD unit, group 2). Both groups did not differ in age, sex, or presence of diabetes. The median follow up was 2293 days (76 months). Patients with high AECA levels were more likely to have normal coronary arteries on angiography (21.6% vs. 16.9%, P = 0.047) and less likely to have calcified lesions (19.0% vs. 26.6%, P = 0.028) and lower prevalence of abnormal renal functions (71.1 mg/dl vs. 66.5 mg/dl, P = 0.033). Patients with higher AECA levels had lower mortality levels (20.1% vs. 27.6%, P = 0.006). A logistic regression model demonstrated independent association between lower AECA levels and the presence of coronary atherosclerosis based on angiogram.

Conclusions: After a median of more than 6 years, higher natural AECA levels were associated with less coronary artery disease and lower mortality rates in patients undergoing coronary angiography