Antipituitary Antibodies in Idiopathic Hyperprolactinemic Patients

Abstract

Hyperprolactinemia is often observed in lymphocytic hypophysitis (LYH). To clarify the possible autoimmune pituitary involvement in patients with apparently idiopathic hyperprolactinemia we investigated the presence of antipituitary antibodies (APA) in hyperprolactinemic patients with idiopathic hyperprolactinemia and in those with prolactinoma. Sixty-six hyperprolactinemic patients (52 F, 14 M age range 28-42 years, group 1) were studied. Of them, 34 out of 66 showed clinical features of hyperprolactinemia and subsequently underwent cabergoline therapy; the 32 out of 66 patients without symptoms of hyperprolactinemia did not receive cabergoline therapy. Moreover, 32 patients (24 F/8M, age range 23-44 years) with hyperprolactinemia due to microprolactinoma (group 2) were also studied. APA, by immunofluorescence method, and anterior pituitary function were evaluated in both groups of patients. APA were present in 17 out of 66 (25.7%) patients in group 1 with titers ranging from 1/16 to 1/64. All patients of group 2 were considered APA negative because these antibodies were found at low titer (<or=1:4) only in five of them. With regard to the function of other pituitary hormones, all APA-negative patients in group 1 and in group 2 showed a normal pituitary function; instead, a partial anterior pituitary impairment was observed in 6 out of 17 (35.3%) APA-positive patients. In asymptomatic patients with apparently idiopathic hyperprolactinemia, APA detection could be useful to disclose forms of potential/subclinical stage of LYH. A future longitudinal study of these patients submitted to cabergoline therapy or free of therapy may be helpful to clarify this assumption.

Pregnancy may favour the development of severe autoimmune central diabetes insipidus in women with vasopressin cell antibodies: description of two cases

“…With regard to the persistence of clinical CDI for some months after delivery in both our cases, a particular role could have been played by PRL. In fact, it has been suggested that lactation and the related increased PRL levels may worsen some autoimmune diseases after delivery (28,29), given the well-known pivotal role played by PRL in the immune system (29). This may explain the prolonged persistence of CDI after delivery in our patients, considering that both cases experienced a normal and complete lactation accompanied by the physiological increase in PRL levels.…”

Postpartum thyroiditis and hypothalamo-hypophysial insufficiency in the same woman with successive pregnancies: a case report

“…Because there are at least five types of cells in the pituitary gland, antibodies to different cell types, to different cell proteins or to different hormones may be the reason, and there are different techniques (like complement fixation, indirect immunoflorescence, immune blotting and enzyme-inked immunosorbent assay) to detect them. Autoantibodies to certain proteins may be positive in 70% of the patients [19] but they can be found in plasma of patients with other pituitary diseases [20].…”

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“…In some cases this is due to very small microprolactinomas which cannot be seen on currently available imaging techniques [39]. Some research suggests that autoimmune pituitary involvement is responsible for idiopathic hyperprolactinemia, where high levels of antipituitary antibodies (25.7%) are found in these patients [40]. PRL levels are usually lower than 100 ng/mL [41].…”