ABSTRACT

Dry eye syndrome (DES) is defined as “a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface”. An estimated 25% of patients attending general ophthalmology clinics reports symptoms of DES. About a quarter of patients with DES has an underlying rheumatic condition, most commonly Sjogren’s syndrome (SS). SS is a multi-system disease with visceral (respiratory, cardiac, renal, gastrointestinal, endocrine, central and peripheral nervous system) and non-visceral (skin, arthralgia, myalgia) systemic clinical conditions. The two essential autoimmune mechanisms in the pathogenesis of SS are: B lymphocyte hyperactivity and focal T lymphocytic infiltration of the exocrine glands. Activation or apoptosis of glandular epithelial cells in genetically predisposed individuals leads to subsequent immune activation, resulting in the expression of auto-antigens that initiate a self-perpetuating T cell-dependent autoimmune response. Multiple pro-inflammatory cytokines, mainly TNF-a, IL-1b and IL-6, chemokines, auto-antibodies and other factors are involved in this process.Unfortunately, SS is quite unknown in the ophthalmology clinics. The main reason of this is the large variations in the symptomatic presentation of the disease, which makes the initial diagnosis difficult. Diagnosing the disease in the early stages would significantly improve the prognosis of this common autoimmune disease. Delay in the diagnosis can cause permanent loss of vision due to corneal complications and other systemic complications. It is of paramount importance that ophthalmologists determine patients who carry significant risk of SS among DES patients, according to the clinical predictors; thus, carefully select the patients in whom SS screening should be conveyed. Herein, we aimed to summarise the immunopathology of SS and the related DES.