AbstractProlactin is known to have immune modulatory effects acting through the prolactin
receptor, which is present on a variety of immune cells. Certain chemokines
contribute to form the type of T helper (Th) preponderance in the immune
response. The objective of this work was to assess if hyperprolactinemia not
related to pregnancy is associated with changes in circulating levels of
chemokines and other immunological markers. In this cross sectional study, 35
patients with hyperprolactinemia (5 men), and 102 healthy blood donors (19 men)
were included. Serum levels of Th1- Th2- and Th17-associated chemokines,
C-reactive protein, immunoglobulins, and the B cell attracting chemokine CXCL13
were assessed. The hyperprolactinemic group had significantly higher levels of
Th2 associated CCL22 (p=0.022), Th17 associated CXCL1 (p=0.001),
B cell attracting CXCL13 (p=0.003), and C-reactive protein
(p<0.001) compared to controls, and these proteins were also positively
correlated with prolactin levels. While differences in CCL22, CXCL1, CXCL13, and
C-reactive protein were present in patients with low or moderate
hyperprolactinemia, no differences were observed at high
(>3600 mU/l) prolactin levels. To evaluate a possible
dose-associated response to prolactin, an in vitro model was used, showing
prolactin-induced increase in T-helper cell activation at moderate levels, while
activation decreased at higher levels. Hyperprolactinemia seems to have several
immunomodulatory effects and was associated with increased levels of chemokines
associated with Th2 and Th17 responses and B cell attraction. However, patients
with greatly increased prolactin had normal levels of chemokines, and in vitro,
high levels of prolactin decreased T-helper cell activation.
Inhibition of T Helper Cell Differentiation by Tacrolimus or Sirolimus Results in Reduced B-Cell Activation: Effects on T Follicular Helper Cells
