PROBLEM: Experimental and clinical evidence has suggested an immunostimulatory effect of prolactin and that bromocriptine, an inhibitor of prolactin release, counteracts the actions of prolactin on the immune system. The aim of this study was to determine the impact of elevated serum prolactin levels on the immune system in patients with pathological hyperprolactinemia.
METHOD: For this purpose, parameters of the cellular and humoral immune system were studied in six women with prolactinomas and one with idiopathic hyperprolactinemia. Studies were performed when serum prolactin concentrations were high as well as during different phases of the menstrual cycle when prolactin levels had been normalized through treatment with bromocriptine.
RESULTS: Hyperprolactinemic subjects, when compared with six age-matched normal women, had significantly higher percentages of total lymphocytes and CD2 + cells. Elevation of CD4 + cells was also observed although to a lesser extent. Bromocriptine-treated patients, when compared with normal women were characterized by increased numbers of total lymphocytes and CD4+ cells, decreased percentage of CD8+ cells, and increased concentrations of serum IgM. These last two findings were also significantly different when compared to those observed in hyperprolactinemia.
CONCLUSION: In this study we have described the changes on cellular and immune parameters in patients with hyperprolactinemia before and during bromocriptine therapy, which support the links of communications between the immune and endocrine systems in humans.