HIGH PREVALENCE OF SUBCLINICAL SJOGRENS-SYNDROME FEATURES IN PATIENTSWITH AUTOIMMUNE THYROID-DISEASE

Objective. To determine the prevalence of keratoconjunctivitis sicca a nd xerostomia related to Sjogren's syndrome (SS) in asymptomatic patie nts with diagnosed autoimmune thyroid diseases (AITD); and to investig ate whether the immunopathologies of sialadenitis observed in AITD ass ociated SS and primary SS are similar. Methods. One hundred seventy-si x patients diagnosed with AITD (88 with Graves' disease, 40 Hashimoto' s thyroiditis, 48 primary myxedema) were tested for keratoconjunctivit is sicca (Schirmer's test and rose bengal staining) and for xerostomia (salivary scintigraphy and labial salivary gland biopsy). Immunohisto pathological studies were performed on cryostat sections of bucal muco sa biopsies using antibodies to CD3, CD4, CD8, CD20, CD14, CD25, LFA-1 , ICAM-3, HLA class II, tumor necrosis factor-alpha, interleukin 1, an d interferon-gamma. Results. Nineteen of 52 (37%) patients with AITD f ulfilled the criteria for xerostomia and 39/170 (23%) for keratoconjun ctivitis sicca. Features of SS were diagnosed in 43 of 176 (24%) patie nts with AITD, with similar prevalence in Graves' (20%), Hashimoto's t hyroiditis (27%), and primary myxedema (29%). In AITD associated SS, i nfiltrating lymphocytes were mainly CD3+ T lymphocytes, with a CD4/CD8 ratio of 2:1. In most patients infiltrating lymphocytes expressed act ivation markers, HLA class IT molecules, and interleukin 2 receptor (C D25). In some patients HLA class II was inappropriately expressed in t he epithelial gland cells. Conclusion. The finding that a third of pat ients with AITD have SS features confirms that AITD and SS are mutuall y associated. Together with the similarity of immunopathology of siala denitis in AITD associated SS in primary SS, this supports the theory that SS and AITD are 2 autoimmune diseases closely related pathogeneti cally.