In 41 primary Sjögren's syndrome patients we compared fatty acid levels within erythrocyte phospholipids, plasma phospholipids, plasma triglycerides and plasma cholesterol esters, with the immunopathological and clinical disease status. Docosahexaenoic acid was the essential fatty acid (EFA), the levels of which correlated (inversely) most closely with the clinical disease status (r=-0.33 to -0.50). Levels of dihomogammalinolenic acid and eicosapentaenoic acid correlated inversely to levels of IgM rheumatoid factors (r=-0.33) and anti-SSA/Ro antibodies (r=-0.40) respectively. Moreover, levels of anti-SSA/Ro antibodies (r=-0.34-0.40) correlated with levels of the proinflammatory arachidonic acid. Sigma n-3 EFA/sigma n-6 EFA ratios correlated significantly to the quantitative estimates of immunopathological and clinical disease status. Our data are in agreement with current understanding of pro- and anti-immunoinflammatory roles within EFA metabolism, and support the rationale for intervention studies.