Prolactin and Autoimmunity

Abstract

The relationship between prolactin and the immune system has been demonstrated in the last two decades, opening new windows in the field of the immunoendocrinology. Prolactin has an important role in the innate and adaptive immune response. Increased prolactin levels have been described in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren syndrome, and systemic sclerosis among others. Hyperprolactinemia is associated with active disease and organ involvement in systemic lupus erythematosus. Therefore, prolactin is an integral member of the immunoneuroendocrinology network and seems to have a role in pathogenesis of autoimmune diseases. Few controlled studies of dopamine agonist treatment in humans with autoimmune disease have been conducted only in systemic lupus erythematosus patients, which support the potential efficacy of such agents even during pregnancy and postpartum. Further studies are necessary to elucidate the mechanisms by which prolactin affects autoimmune disease activity, increase the inflammatory mechanism, and determine the role of anti-prolactinemic drugs to regulate the immune/inflammatory process.

Prolactin promotes cartilage survival and attenuates inflammation in inflammatory arthritis

“…Although the role of endogenous PRL in autoimmune diseases has generated controversies (57)(58)(59)(60)(61)(62)73), our study reveals that elevating serum PRL levels significantly attenuates cartilage death and joint inflammation in inflammatory arthritis. This strategy may be comparable to the well-established use of glucocorticoids in patients with RA, in which levels of the endogenous hormones appear insufficient to control the disease (74).…”

“…A large body of literature has focused on PRL having a pathogenic role in RA and also in other autoimmune diseases, like SLE, Sjögren's syndrome, Hashimoto's thyroiditis, celiac disease, MS, etc. Its pathogenic role is largely based on the preponderance of autoimmune diseases in women (56) and on PRL being a sex-linked hormone, on the higher levels of circulating PRL detected in some patients (6%-45%, depending on the disease and specific study), on the therapeutic effects of the dopamine agonist bromocriptine, and on the immunoenhancing properties of PRL (57)(58)(59)(60)(61). However, in RA, as in the other autoimmune diseases, treatment with bromocriptine is not always effective and the association between PRL levels Bax, and p53 mRNA levels in ankle joints from PRL-treated and nontreated rats on day 21 after CFA (n = 3-8).…”

“…Bars represent mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001. and disease activity has been inconsistent (58)(59)(60)(61)(62). Generalizations are confounded by the contribution of PRL synthesized locally by cells like chondrocytes (12), synoviocytes and immune cells (16), and endothelial cells (63), which can potentiate the action of systemic PRL.…”

“…The variability of the relationship between PRL and autoimmune diseases is further highlighted under physiological hyperprolactinemia. During pregnancy, when PRL levels are high, SLE flare-ups occur, but RA and MS go into remission (59,68). Breastfeeding, a stimulus elevating circulating PRL, exacerbates SLE in humans (69), but it is protective in the B/W mouse model of SLE (70).…”

Kronisk inflammatorisk artritt og svangerskap

“…Tett sykdomskontroll er viktig for å begrense graden av sykdomsoppblussing og for at pasienten kan starte så tidlig som mulig med adekvat sykdomsmodifiserende behandling (51). I forbindelse med amming øker produksjonen av prolaktin som også kan stimulere den inflammatoriske prosessen (52,53). Det er likevel sjelden pasienter blir frarådet å amme som ledd i å redusere den inflammatoriske aktivitet.…”