Pituitary antibodies and lymphocytic hypophysitis

Lymphocytic hypophysitis (LYH) is a pituitary disease which can cause headache, changes in visual field and pituitary dysfunction. The clinical, histopathological and morphological findings and its association with other autoimmune disorders allow LYH to be included among the autoimmune diseases. Pituitary trans-sphenoidal biopsy is thought to be the diagnostic gold standard for LYH, even if some morphological findings on hypothalamic–pituitary magnetic resonance imaging (MRI) can suggest the occurrence of this disease. Despite the fact that organ-specific antibodies are good markers of many autoimmune endocrine diseases, the pathogenetic and diagnostic roles of anti-pituitary antibodies (APAs) in LYH are still under discussion. In fact, several methods have been used to detect APAs, but the conflicting results from different methods have impaired the clinical relevance of these antibodies. Recently, APAs have been detected by an immunofluorescence method in patients with selective idiopathic hypopituitarism (particularly in those with growth-hormone deficiency) and in adults with autoimmune endocrine diseases. The results suggest that only when they are present at high titres may they be considered a good marker of pituitary involvement, and in particular of growth-hormone-producing cells.