Background: Neuroendocrine factors play an important role in the expression of autoimmune diseases. Prolactin (PRL) can induce T-cell proliferation and macrophage activation. Elevated PRL levels have been described in patients with rheumatoid arthritis (RA).
Aim and methods: We studied immunological and clinical effects of PRL suppression in 9 RA patients with active disease, treated for 3 months with bromocriptine (BRC), an inhibitor of PRL secretion.
Results: BRC induced a significant depression of the peripheral blood mononuclear cells response to antigen (p = 0.008) and mitogen (p = 0.008) which was significantly correlated with improvements in the HAQ disability index (r = 0.68; p = 0.04) and grip strength (r = 0.7; p = 0.02). Also, the in-vitro production of IL-2, nitric oxide and poliamines--that are critical for the proliferative response of lymphoid cells--decreased significantly. The group experienced significant improvement of grip strength (p = 0.028) and the HAQ disability index (p = 0.025), whereas 4 individuals achieved clinical improvement according to the American College of Rheumatology preliminary definition. We conclude that BRC treatment induces a significant depression of in-vitro immune function in RA patients and that these changes are related to parameters of disease activity. The effects of BRC on immune function and disease activity in RA patients warrant further investigation.