Prolactin and autoimmunity: The hormone as an inflammatory cytokine.

Nowadays, more than 80 autoimmune disorders are recognized, in which an aberrant immune response against different organs and tissues plays a crucial role. Hormonal homeostasis has great influence in achieving competent and healthy immune system function. Prolactin has a bioactive function acting as a hormone and a cytokine. It influences the immune system modulation, mainly inhibiting the negative selection of autoreactive B lymphocytes. Hyperprolactinemia has been detected in many patients with different autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, Sjögren syndrome, multiple sclerosis, autoimmune thyroid disease, systemic sclerosis, among others, and its believed to play a crucial role in disease pathogenesis. A direct correlation between prolactin levels and disease activity was not clear. Genetic factors may have a role in humans as in animal models. Dopamine agonists have proven to offer clinical benefits among autoimmune patients and represent a promising therapy to be explored. In this review, the authors attempt to provide a critical overview on the role of prolactin in the immune system, exploring its contribution to the development of autoimmune diseases.

Exacerbations of autoimmune diseases during pregnancy and postpartum.

Autoimmune diseases represent a complex heterogeneous group of disorders that occur as a results of immune homeostasis dysregulation and loss of self-tolerance. Interestingly, more than 80% of the cases are found among women at reproductive age. Normal pregnancy is associated with remarkable changes in the immune and endocrine signaling required to tolerate and support the development and survival of the placenta and the semi-allogenic fetus in the hostile maternal immune system environment. Gravidity and postpartum represent an extremely challenge period, and likewise the general population, women suffering from autoimmune disorders attempt pregnancy. Effective preconception counseling and subsequent gestation and postpartum follow-up are crucial for improving mother and child outcomes. This comprehensive review provides information about the different pathways modulating autoimmune diseases activity and severity, such as the influence hormones, microbiome, infections, vaccines, among others, as well as updated recommendations were needed, in order to offer those women better medical care and life quality.

Prolactin and Autoimmunity.

The great asymmetry of autoimmune diseases between genders represents one of the most enigmatic observations among the mosaic of autoimmunity. Sex hormones are believed to play a crucial role on this dimorphism. The higher prevalence of autoimmunity among women at childbearing ages, disease onset/relapses during pregnancy, and post-partum are some of the arguments that support this hypothesis. Certainly, motherhood represents one of the most remarkable challenges for the immune system, which not only has to allow for the conceptus, but also has to deal with complex endocrine alterations. Hormonal homeostasis is known to exert a crucial influence in achieving a competent and healthy immune system. Prolactin (PRL) has a bioactive function acting as a hormone and a cytokine. It interferes with immune system modulation, mainly inhibiting the negative selection of autoreactive B lymphocytes. Likewise, hyperprolactinemia has been described in relation to the pathogenesis and activity of several autoimmune disorders. Dopamine is an effective inhibitor of PRL secretion due to either a direct influence on the hypophysis or stimulation of postsynaptic dopamine receptors in the hypothalamus, arousing the release of the PRL inhibitory factor. Hence, dopamine agonists have proven to offer clinical benefits among autoimmune patients and represent a promising therapy to be explored. In this review, we attempt to provide a critical overview of the link between PRL, autoimmune diseases, and motherhood.