Cellular and humoral immune parameters in women with pathological hyperprolactinemia before and during treatment with bromocriptine

Immune function in hypopituitarism: time to reconsider?

Hypopituitarism is not currently considered as a potential cause of immune disruption in humans. Accumulating data from in vitro and animal models support a role for the pituitary gland in immune regulation. Furthermore, the increased mortality risk noted in patients with adult hypopituitarism remains poorly explained and immune dysfunction could conceivably contribute to this observation. In a recent issue of Clinical & Experimental Immunology, we presented new data relating to immune status in adults with treated, severe hypopituitarism. We observed humoral immune deficiency in a significant proportion, despite stable pituitary replacement, including growth hormone (GH). This was especially evident in those with low pretreatment IGF-I levels and appeared independent of anticonvulsant use or corticosteroid replacement. These observations require substantiation with future studies. In this short review, we summarize existing data relating to the effects of pituitary hormones on immune function and discuss potential clinical implications surrounding the hypothesis of immune dysregulation in severe hypopituitarism.

Serum prolactin concentrations in patients infected with human immunodeficiency virus

PURPOSE

To analyze the prevalence, effects of HAART, and implications of hyperprolactinemia in HIV-infected patients.

METHOD

192 HIV-infected men in stable clinical condition who underwent 355 measurements of prolactin were prospectively studied. Other clinical, immunologic, virologic, and laboratory parameters were also evaluated at the time of each prolactin measurement.

RESULTS

Hyperprolactinemia was observed in 21.4% of the patients. Hyperprolactinemia was more commonly found in patients receiving opioids than in those who were not (p =.03), but it was not influenced by a past diagnosis of AIDS, presence of metabolic disturbances, gynecomastia, or viral load. Patients noninfected with hepatotropic viruses had slightly higher prolactin levels than those who were infected (p =.049). There were significant differences in the rates of hyperprolactinemia according to different CD4 strata, with higher rates in patients with higher CD4 counts. Similarly, hyperprolactinemic patients had higher CD4 counts than patients with normal prolactin (p =.038). Antiretroviral therapy was not associated with prolactin levels.

CONCLUSION

Hyperprolactinemia is a common finding in HIV infection and is observed in about one fifth of male patients in stable clinical condition. It is not related to antiretroviral therapy, metabolic disturbances, liver disease, or viral load. The implications of its association with CD4 counts are unclear and should be investigated.

Bromocriptine in rheumatic and autoimmune diseases

BACKGROUND AND OBJECTIVES

Multiple lines of evidence support the concept that the anterior pituitary hormone prolactin has a pathogenic role in rheumatic and autoimmune diseases including, but not limited to, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Reiter's syndrome, psoriatic arthritis, and uveitis. Conversely, the dopaminergic agonist bromocriptine appears to have therapeutic effects through suppression of pituitary prolactin secretion and, perhaps, through actions on peripheral dopamine receptors. This article reviews the experimental and clinical data supporting the therapeutic use of bromocriptine as a nonstandard or adjunctive therapy in rheumatic and autoimmune diseases.

METHODS

Data addressing the potential therapeutic role of bromocriptine in rheumatic and autoimmune diseases, as well as frequently associated comorbidities, was accumulated from the author's work, online literature search of the National Library of Medicine, and references from these identified publications.

RESULTS

There have been a number of clinical therapeutic trials using 2.5 to 30 mg of bromocriptine per day in a single or divided dose, which have shown efficacy with minimal side effects in the treatment of rheumatic and autoimmune diseases. In RA, bromocriptine administration has induced immunosuppression of several immune parameters and has been associated with improvements in morning stiffness, grip strength, numbers of swollen/painful joints, and the Health Assessment Questionnaire disability index. In two blinded studies, bromocriptine reduced the number of SLE flares and was as effective as hydroxychloroquine in reducing lupus disease activity indices, respectively. In case reports, bromocriptine has been used successfully in the treatment of Reiter's syndrome enthesopathy and psoriatic arthritis. The potential efficacy of bromocriptine in the treatment of uveitis and multiple sclerosis is suggested but remains to be verified.

CONCLUSIONS

Double-blind, placebo-controlled studies are limited, but clinical observations and trials support the use of bromocriptine as a nonstandard primary or adjunctive therapy in the treatment of recalcitrant RA, SLE, Reiter's syndrome, and psoriatic arthritis and associated conditions unresponsive to traditional approaches. Additional investigation is needed to verify this conclusion and extend preliminary results.

RELEVANCE

In patients with rheumatic and autoimmune diseases, bromocriptine may be a relatively safe and efficacious alternative therapy. Semin Arthritis Rheum 31:21-32.

The uncoupled couple? Prolactin and CD4 lymphocytes in HIV infection

The possible role of prolactin (PRL) in human immunodeficiency virus (HIV) infection is unknown, despite the modulatory role of this hormone in humoral and cell-mediated immune responses. Recent studies have evidenced: (a) intralymphocyte synthesis of dopamine (DA) which down-regulates their own proliferation and differentiation; (b) decreased DA but increased PRL concentrations in cerebrospinal fluid of HIV-infected men; and (c) diminished hypothalamic DA tone in HIV-infected men. The present hypothesis proposes that, in HIV-infected men, a diminished generalized DA tone exists to stimulate human lymphocyte proliferation and differentiation at a maximum possible rate by: (1) decreasing the inhibitory influence of intralymphocyte DA; and (2) maintaining pituitary and extrapituitary (i.e. lymphocyte) PRL synthesis and release as high as possible. If this hypothesis is correct, it may have a potentially important therapeutic implication: the possibility to rebuild the battered immune system in HIV-infected patients from inside the body in a physiologic manner by the parenteral administration of recombinant human PRL.

Impaired metoclopramide-induced pituitary prolactin release in men with human immunodeficiency virus infection

To investigate whether metoclopramide-induced prolactin release is impaired in HIV-infected men, we studied 10 clinically healthy HIV-negative adult men (group 1) and 10 consecutive HIV-positive adult men (group 2) with anti-HIV antibodies confirmed by Western blot analysis and a CD4 cell count from 13 to 570x10(6)/L. After a 10- to 12-hour overnight fast, three basal blood samples were obtained at 15-minute intervals (-30, -15, and 0 minutes) and thereafter at 15, 30, 60, 90, 120, 180, and 240 minutes after a 10-mg intravenous bolus of metoclopramide. Duplicate serum prolactin concentrations were measured in each sample with commercially available radioimmunoassay kits. No significant differences between groups were observed in basal prolactin levels. Group 2 had lower serum prolactin concentrations than group 1 throughout the test (P< or =.002). The area under the prolactin curve (mean +/- SD) was also lower in group 2 than in group 1 (7156+/-1433 ng/mL/240 min vs. 12430+/-2454 ng/mL/240 min, P<.0001), and the area under the prolactin curve had a significant correlation with the CD4 cell counts (r = 0.7912, P<.001). These findings suggest that the hypothalamic dopaminergic tone, although present, was clearly diminished in these HIV-positive men regardless of their clinical stage.