The effect of prolactin and bromocriptine on human peripheral immune status

The aim of this study was to determine the influence of elevated serum prol actin (PRL) levels on the peripheral lymphocyte subsets in patients with hy perprolartinemia. For this purpose we studied 20 hyperprolactinemic patient lymphocyte subsets by flow cytometry on their hyperprolactinemic state and after their serum prolactin concentration was normalized with bromocriptin e (BC) alone or BC and surgery. We observed decreased absolute numbers and percentage of Natural Killer (p=0.0009 and 0.0001, respectively) and CD3/CD 25 lymphocytes (p= 0.009 and 0.002) in hyperprolactinemic patients, compare d to 8 sex- and age-matched normal controls. There was no correlation betwe en PRL levels and CD16/56 and CD3/CD25 numbers (p=0.72 and 0.33, respective ly). We did not find any significant difference in absolute numbers (p=0.95 ) and percentage (p=0.84) of B-lymphocytes of hyperprolactinemic patients, as compared with normal controls. We did not detect any increase in absolut e cell numbers of CD16/CD56 (p=0.21) and CD3/CD25 (p=0.61) of BC-treated pa tients when compared to their hyperprolactinemic state. We demonstrated an increase in CD8-cells (p=0.0173) and a decrease in CD4/CD8 ratio (p=0.036) in hyperprolactinemic patients treated with BC. There was also an increase in the number of activated T-cells (CD3/HLA DR) in this group, compared to normal controls and the hyperprolactinemic state of the same patients (p=0. 04). In conclusion, elevated PRL levels do not lead to an "overstimulation" of the B-cells, but deteriorate the cytotoxic function.