Chemokine tear levels in primary Sjögren’s syndrome and their relationship with symptoms

Purpose To evaluate CCL2, CXCL8, and CXCL10 in the tears of patients with Primary Sjögren’s syndrome (PSS) and correlate them with ocular symptoms/discomfort and objective ocular tests. Methods We studied 21 patients with PSS. A single ophthalmologist, expert in dry eye, examined the patients and assessed tear film breakup time, Schirmer I test, tear meniscus height, Van Bijsterveld staining score and SICCA Ocular Staining Score. We also assessed the ESSPRI and ocular dryness VAS and the Ocular Surface Disease Index (OSDI), a 12-item scale assessing symptoms associated with dry eye disease and their impact on vision (ocular symptoms/discomfort). Tear samples collected with sterile tear flow strips were frozen at -86 °C until testing. After thawing, tears were extracted from the strips. We tested CCL2, CXCL8, and CXCL10 by luminometry. We also included 21 healthy control subjects without a dry eye. Results CXCL8 levels were similar in patients and controls. PSS patients had lower levels of CXCL10 (472.8 vs. 1652 pg/μL, p = 0.009) and CCL2 (1.08 vs. 9 pg/μL, p = 0.0001) than controls. Patients with worse ocular sicca symptoms/discomfort had the lowest CXCL10 levels (239.3 vs. 646.2 pg/μL, p = 0.02). CCL2 correlated with tear meniscus height ( τ = 0.37, p = 0.02) and with OSS ( τ = -0.3, p = 0.05). Conclusions We found lower levels of CXCL10 and CCL2 in the tears of patients with PSS, associating the former with worse ocular symptoms and the latter with positive ocular target tests.