There is growing evidence to indicate that there is a strong association between changes in the immune system and the development of hypertension in both animal models and humans. Alterations in immune function in hypertension are generally accompanied by an increase in the level and secretion of immunoglobulin, a decrease in the number and function of T-lymphocytes, genetic predisposition, auto-antibodies against nuclear structure, smooth muscle cells, native thymus tissue and G-protein-coupled cardiovascular receptors. Although there is evidence from a variety of observations to suggest that an abnormal immune system is involved in the pathogenesis of hypertension, the immunological mechanism and the specific role of changes in the immune system in the development of hypertension have not been elucidated.