Reduced 25-hydroxyvitamin D Levels in Primary Sjögren's Syndrome: Correlations to disease manifestations

The purpose of this study was to explore the clinical and pathogenic significance of vitamin D metabolites in primary Sjögren's syndrome (primary SS). We measured blood concentrations of 25-hydroxyvitamin D (25 OH D) and calcitriol (1,25(OH)2D)vc in 41 patients and correlated the results with blood levels of various immune activation products, as well as with patients' clinical status. Levels of 25 OH D were slightly decreased as compared to normal controls and the reduced levels of 25 OH D were stable over the observed period of 2 years. Levels of 25 OH D correlated inversely with levels of soluble interleukin-2 receptor, status indices for global disease, total exocrine disease, surface exocrine disease, internal organ exocrine disease, and mediator-induced disease. Levels of 1,25(OH)2D varied considerably and compared to normal control values. Levels of 1,25(OH)2D did not correlate with clinical/immunopathological status. In conclusion the inverse correlations found between levels of 25 OH D and measures of clinical and immunoinflammatory status support the notion that vitamin D metabolism may be involved in the pathogenesis of primary SS.