Improvement of conjunctival cytological grade and tear production in Ankylosing Spondylitis patients under TNF inhibitors: a long-term follow-up

Dry eye disease can compromise the patient’s quality of life. Few studies assessed the ocular surface (OS) in Ankylosing Spondylitis (AS) patients. This study aimed to evaluate the clinical and cytological findings of the OS in patients with AS, classify dry eye disease (DED) severity grade and conjunctival impression cytology (IC), and the effects of TNF inhibitors (TNFi) in a one-year follow-up. A baseline (BL) evaluation included 36 AS patients and 39 healthy controls. They fulfilled the Ocular Surface Index Disease questionnaire and underwent the Schirmer I test, break-up time, vital staining, and conjunctival IC. A DED severity grade, as well as IC rating, was applied. Fourteen of these patients received TNFi and analysis of ocular and systemic AS disease parameters occurred at BL and three months (3 M), and 12 months (12 M) after treatment. The AS patients presented a higher frequency of DED (p = 0.01), a worse score of severity (p = 0.001), and a higher frequency of altered IC (p = 0.007) when compared to controls. The 14 patients under TNFi presented an improvement in all the clinical disease activity parameters throughout the one-year treatment (p < 0.05) even as a concomitant increase in the Schirmer test (p = 0.04), and a significant amelioration in the altered IC to a normal IC (p = 0.006). DED is a frequent and under-diagnosed ocular disease in AS patients. The long-term parallel improvement of disease activity and OS parameters in AS patients receiving TNFi suggests that the OS can be an additional target of systemic inflammation in AS.