Supplementary Material for: The Monocyte-to-Lymphocyte Ratio Correlates with Psycho-Neuro-Inflammatory Factors in Patients with Stable Coronary Artery Disease

Background: Psychosocial stress and depression have been recognized as major risk factors of coronary artery disease (CAD). Although monocytes are known to be key players in atherosclerosis, monocyte-based associations with psychoneuroendocrino-immuno-inflammatory (PNI) markers have not been widely investigated in stable CAD. Objective: We examined associations between the monocyte-to-lymphocyte ratio (MLR) and key PNI markers in stable CAD. Methods: We studied 23 patients with stable CAD who completed the Beck Depression Inventory (BDI) and Rahe's Brief Stress and Coping Inventory. A white blood cell differential was performed, and levels of cortisol, chromogranin A (CgA), LL-37, interleukin-6 (IL-6) and C-reactive protein (CRP) were assayed in plasma. Results: Monocyte fraction, MLR and plasma CgA levels exceeded reference values, the social support score was low, and 7 patients had elevated BDI scores. In the multivariate-adjusted analysis, a higher MLR was associated with greater depressive symptom severity (r = 0.624, p < 0.01) as well as with higher concentrations of CgA (r = 0.660, p < 0.01), LL-37 (r = 0.643, p < 0.01), IL-6 (r = 0.532, p < 0.05) and CRP (r = 0.470, p < 0.05). BDI scores associated with CgA concentration (r = 0.618, p < 0.01) and CgA level correlated negatively with the social support score (r = -0.511, p < 0.05). Conclusions: Our findings suggest that, in patients with stable CAD, elevated MLR may be associated with depressive symptoms, with increased neuroendocrine-sympathetic activity (marked by CgA) and inflammatory markers that are pertinent to atherosclerosis initiation and progression. The increased neuroendocrine-sympathetic activity correlated with low social support and depressive symptom severity. The MLR might serve as an easy-to-obtain and inexpensive proxy measure of an activated PNI network in stable CAD.