Omega-3 and omega-6 fatty acids in primary Sjögren'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 ω-3 and ω-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 ω-3 (α-linolenic acid [α-LN], eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA]) and ω-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 ω-3 and ω-6 intake was lower in SS patients than controls, and did not correlate with serum levels. We found a negative correlation between α-LN and the OSDI and ESSDAI, as well as DHA and ESSDAI. In tears, AA positively correlated with CXCL9, whereas in saliva, α-LN, DHA and the ω3 sum negatively correlated with CCL2. We observed a negative correlation between the ω6 sum and IL-21. CONCLUSIONS pSS patients had deficient omega intake. Lower ocular symptoms, ESSDAI scores and salivary CCL2 correlated with higher ω-3 levels, possible suggesting a role in chronic inflammation. Further studies are warranted to deepen in the knowledge of this association.