Although the exact mechanisms of the benefits of Zn supplementation remain unknown, the immunomodulatory and neurological effects of Zn could be speculated upon; inverse associations were reported between a low Zn level and an increased CD4+/CD8+ T cell ratio [24,31], which could contribute to the clinical symptomatology and neuro-progressive pathways in depression. The gene discussed is CD4; the disease is depressive symptom measurement.