Sjögren’s syndrome can’t be diagnosed in one fell swoop. It usually takes a few different medical professionals comparing notes before the autoimmune condition can be recognized. A dentist may notice a lack of saliva while a rheumatologist may chart the patient’s joint pains and an optometrist observes dry eye symptoms.1 Individually, these symptoms are vague, and even when put together they only suggest Sjögren’s.1 However, researchers are now suggesting that biomarkers found in tears may help indicate whether a patient’s dry eye is related to Sjögren’s or not.
Specifically, the investigators report that tear levels of a goblet cell–specific mucin called MUC5AC combined with interleukin (IL)-8 can help make the diagnosis.2 They conducted a prospective, observational, case-controlled study of 62 patients, 21with a definitive diagnosis of Sjögren’s dry eye, another 20 with non-Sjögren’s dry eye and 21 age-matched healthy controls with no history of either. They tested subjects with noninvasive tear break-up time, tear osmolarity, tear sampling, Schirmer test without anesthesia and ocular surface staining (lissamine green and fluorescein).2
Their analysis found the conjunctival lissamine green staining score was significantly greater in patients with Sjögren’s than those with non-Sjögren’s dry eye.2 This greater conjunctival staining was also associated with a reduction in tear MUC5AC. Among the tear cytokines, the researchers noted a significant association between IL-8 levels and Sjögren’s dry eye.2 When the team classified the patients based on their tear MUC5AC levels, the found significantly increased tear IL-8 levels in those with Sjögren’s-related dry eye, but not those with non-Sjögren’s dry eye.2
1. Diagnosis of Sjögren’s syndrome. Johns Hopkins Sjogren’s Center. www.hopkinssjogrens.org/disease-information/diagnosis-sjogrens-syndrome. Accessed March 27, 2020.
2. Akpek E, Wu H, Karakus S, et al. Differential diagnosis of Sjogren versus non-Sjogren dry eye through tear film biomarkers. Cornea. March 13, 2020. [Epub ahead of print].