Inequality in health and its multiple dimensions is an essential aspect of social injustice. Several studies have shown that mental and physical health in adulthood is not a phenomenon independent of one’s childhood. Those from lower socioeconomic status have higher mortality and shorter life expectancy. Individualism and utilitarianism in social relationships have led to a wide range of social instability, poverty, deprivation, and inequality in societies. In addition to widespread social effects, they have made harmful consequences on the basic vital systems and organs through interference with multiple biological processes. In modern societies, people live in highly stressful situations, and several studies have pointed a strong relationship between the higher prevalence of diseases and social and physiological stresses. Studies of normal and experimental situations also showed their significant effects on the immune response. Accordingly, increased incidence of invasive behaviors has been associated with increased cytokines and immune-cellular activity in animal studies. According to the stimulus type and contact duration, chronic stress influences both innate and acquired immune factors. Stress affects the immune system via activation of the hypothalamus-pituitary-adrenal axis and affects the innate immune agents such as monocytes, macrophages, and proinflammatory cytokines, causing the increase of stress hormones (glucocorticoid-catecholamines). Chronic stress influences the acquired immune components by changing the immune cell population and altering the balance between immune cells and their secreted cytokine levels.