Omega-3 and omega-6 fatty acids in primary Sjogren's syndrome: clinical meaning and association with inflammation.

OBJECTIVES: Lipid mediators derived from polyunsaturated fatty acids (FA), have been related to inflammation and immune response regulation. Herein we evaluated the intake and serum levels of omega-3 and omega-6 FA among patients with primary Sjogren's syndrome (pSS), and correlated with ocular/oral sicca symptoms, disease activity and a panel of chemokines/cytokines. METHODS: We included 108 patients and 100 controls. Dietary information was obtained from a food questionnaire of one-day reminder and processed using a nutritional software. Among the SS group, we measured serum omega-3 (alpha-linolenic acid [alpha-LN], eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA]) and omega-6 (linoleic acid [LA], arachidonic acid [AA]) by gas chromatography flame ionization. We scored the ESSDAI, ESPRI, Schirmer-I test and NSWSF. In a subsample, we assessed the OSDI, ophthalmologic staining scores and measured CXCL8, CXCL10, CCL2, IL-22 and IL-21 in saliva, and CXCL8, CXCL10, CCL2 and CXCL9 in tears by Luminometry. RESULTS: omega-3 and omega-6 intake was lower in SS patients than controls, and did not correlate with serum levels. We found a negative correlation between alpha-LN and the OSDI and ESSDAI, as well as DHA and ESSDAI. In tears, AA positively correlated with CXCL9, whereas in saliva, alpha-LN, DHA and the omega3 sum negatively correlated with CCL2. We observed a negative correlation between the omega6 sum and IL-21. CONCLUSIONS: pSS patients had deficient omega intake. Lower ocular symptoms, ESSDAI scores and salivary CCL2 correlated with higher omega-3 levels, possible suggesting a role in chronic inflammation. Further studies are warranted to deepen in the knowledge of this association.