LAUSR

Dear Editor, Sj€ ogren’s syndrome (SS) is an autoimmune disease characterized by dryness of the eyes and mouth, which is because of the destruction of salivary and lacrimal glands by infiltrating lymphocytes. Patients with SS have an increased risk of developing malignancies, particularly non-Hodgkin B cell lymphoma and solid cancers such as breast cancer or thymoma. However, there have been no previous reports of prolactinoma in a patient with SS. Prolactin might play a role in the pathogenesis of some rheumatic diseases, including SS. Several cases of prolactinoma have been reported with concomitant systemic lupus erythematosus (SLE), which generated much interest in the possibility that prolactin influences SLE disease activity. Here we report the first case of SS associated with prolactinoma in which SS-related symptoms of dryness were relieved by a dopaminergic agonist. A 21-year-old woman was initially diagnosed with conjunctivitis sicca at a local ophthalmic clinic. She had used artificial tears more than three times per day. She had also suffered from mouth dryness from the age of 26 years and recurrent lymphadenopathy behind both ears from the age of 28 years. She did not use any medication that would cause dryness. Her blood test results were positive for anti-nuclear antibodies (ANA, 1:320, speckled and cytoplasmic pattern), anti-Ro/ SSA, anti-La/SSB, and anti-thyroglobulin antibodies (Abs, > 4000 IU/mL). Tests for double-stranded DNA, Sm, anti-phospholipids and anti-cyclic citrullinated peptide Abs were negative. However, a Schirmer test was positive. A Tc-99 m pertechnetate salivary scan revealed decreased absorption and excretion in both the parotid and submental glands (Fig. 1). Mild focal perivascular lymphocytic infiltration was observed in a minor salivary gland biopsy. The diagnosis of SS was confirmed according to the American European Consensus Criteria. The patient was also diagnosed with Hashimoto’s thyroiditis and began undergoing synthyroid and pilocarpine treatment. The patient revisited our hospital at the age of 33 years because of galactorrhea and oligomenorrhea. At that time, her blood test results revealed an increase in prolactin to 221.9 ng/mL (normal range; 4.79–23.3 ng/mL). Sellar magnetic resonance imaging identified a focal lesion on the right pituitary gland (Fig. 2). Based on these findings, she was diagnosed with prolactinoma and began undergoing treatment with the dopaminergic agonist bromocriptine mesylate. Bromocriptine treatment improved her symptoms of dryness, allowing her to reduce the use of artificial tears and pilocarpine as her prolactin level decreased (3.27 ng/mL). However, after ceasing bromocriptine treatment for 2 weeks, she suffered from severe mouth and eye dryness and a rebound in prolactin levels (60.57 ng/mL). These symptoms again improved after restarting bromocriptine treatment. At present, the patient has been treated with synthyroid and bromocriptine for 6 months and has had no recurrence of severe dryness during follow-up. Prolactin, which stimulates diverse cell types such as macrophages, dendritic cells, T cells and B cells, has been considered both a pathogenic and protective factor in autoimmune inflammation; however, the role of prolactin in autoimmune disease remains controversial. A recent study revealed that the detrimental effects of prolactin in the context of autoimmune disease prevailed in B cell-dominated diseases such as SLE, by inducing the production of autoantibodies and mature B cells. Although the pathogenic role of prolactin in SS has not yet been revealed, prolactin might also be related to B lymphocyte hyper-reactivity in patients with SS. In addition, prolactin-like proteins are synthetized and overexpressed in the glandular epithelial cells of labial salivary glands and the acinar cells of lacrimal glands, and these proteins exert important bioactive effects on immune function. Prolactin, which inhibits the apoptosis of transitional B cells and increases antibody secretion, contributes to the onset of SS through its immunostimulatory effects. Taken