Abnormal vitamin D3 metabolism in patients with primary Sjogren's syndrome

Abstract

Recent studies have suggested that vitamin D3 may have an immunoreglatory role in vitro. The vitamin D3 metabolism in 35 patients with primary Sjigren's syndrome was investigated by measuring blood concentrations of la,25- dihydroxyvitamin D3 (la,25-(OH)2D3) and 25- hydroxyvitamin D3 (25-OHD3), as weil as phenotypes and blood concentrations of Gc globulin, the main vitamin D3 binding protein in the blood. 25-OHD3 concentrations were diminished, but those of la,25-(OH)2D3 were normal. There was no significant difference between the distribution of Gc phenotypes in the patients with pma Sjgren's syndrome and normal controls. Likewise, blood concentrations of Gc globulin corresponded to normal values. Among patients with increased concentrations of IgM rheumatoid factor there was a significant negative correlation between the serum titres of 1gM rheumatoid factor and 25-O0I)3 concentrations.