The aim was to investigate the levels of cytokines and soluble IL-6R in the tears of patients with thyroid-associated orbitopathy (TAO) disease. Schirmer’s test was adopted to collect tears from TAO patients (N = 20, 17 women, mean age (±SD): 46.0 years (±13.4)) and healthy subjects (N = 18, 10 women, 45.4 years (±18.7)). Lacrimal cytokines and soluble IL-6R (sIL-6R) were measured using a 10-plex panel (Meso Scale Discovery Company) and Invitrogen Human sIL-6R Elisa kit, respectively. Tear levels of IL-10, IL-12p70, IL-13, IL-6 and TNF-α appeared significantly higher in TAO patients than in healthy subjects. Interestingly, IL-10, IL-12p70 and IL-8 levels increased in tears whatever the form of TAO whereas IL-13, IL-6 and TNF-α levels were significantly elevated in inflammatory TAO patients, meaning with a clinical score activity (CAS) ≥ 3, compared to controls. Furthermore, only 3 cytokines were strongly positively correlated with CAS (IL-13 Spearman coeff. r: 0.703, p = 0.0005; IL-6 r: 0.553, p = 0.011; IL-8 r: 0.618, p = 0.004, respectively). Finally, tobacco use disturbed the levels of several cytokines, especially in patient suffering of TAO. The differential profile of lacrimal cytokines could be useful for the diagnosis of TAO patients. Nevertheless, the tobacco use of these patients should be taken into account in the interpretation of the cytokine levels.

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PurposeTears are known as lubricating the eyes and ensuring nutrition and protection of the surrounding ocular tissues. However, its composition is the result of a dynamic system, which is dependent on various stimuli, including ocular and systemic diseases. Here, we propose that, tears could represent an innovative source of biomarkers in thyroid‐associated orbitopathy (TAO) disease.MethodsSchirmer's test was adopted to collect tears from TAO [n = 20, 3 males, mean age (±SD): 46.0 years (±13.0)] and healthy patients [n = 18, 8 males, 45.4 years (±18.7)]. Independent isobaric proteomics experiments were carried out and analyzed on a linear trap quadrupole Orbitrap Velos Pro. Easyprot software was used to obtain protein identification and quantification (2 unique peptides, 1% FDR, ratio<0.66 or >1.5, p‐value>0.05). Biological process and pathways were analyzed using Ingenuity pathway analysis software (6.7 version). Verification of proteins was performed by Western Blot or immunoassays.ResultsGlobally, 646 proteins were identified and 62 were considered as differentially expressed (27 up‐and 35 downregulated). Interestingly, among them, the acute phase response signalling and glycolysis pathways were mainly represented. Verification is ongoing for these candidates. In parallel, we observed that the levels of IL‐6, IL‐10, IL‐12 and TNF‐α, were significantly upregulated in tears of TAO patients.ConclusionsThese results confirmed tears as a suitable source to discover biomarkers for TAO disease. Moreover, the emergence of proteins involved in the glycolysis, associated to inflammation, could bring new general knowledge about TAO that still remains not well characterized. This study is kindly supported by the Provisu foundation and the SNF_MHV (PMPDP3_158370).