B-Cell-Activating Factor (BAFF) Correlated with Serum Vitamin D Values—Possible Markers with a Prognostic Role in Thyroid Autoimmune Diseases

<b>Objectives:</b> The aim of this study was to find correlations between vitamin D deficiency and thyroid autoimmune pathology in a group of patients from Dobrogea, a non-endemic geographical area, with a high degree of sunshine. An important factor in maintaining immunological balance is the intake of an adequate level of vitamin D. Multiple studies have suggested that vitamin D deficiency is associated with a higher incidence of autoimmune diseases. Recent studies have analyzed the possible effect of this factor in promoting autoimmunity, as the serum level of BAFF often increases among patients with systemic autoimmune diseases. <b>Methods:</b> This study included 80 patients with autoimmune thyroid pathology from the Dobrogea area. The entire study group (<i>n</i> = 80) was divided according to the established diagnosis into two study groups: Group 1 included 62 patients with CAT (chronic autoimmune thyroiditis), and Group 2 included 18 patients with GD (Graves' disease). <b>Results:</b> Vitamin D study average values of 25-OH-vitamin D found statistically significant differences between vitamin D values in the two groups (<i>p</i> = 0.018). Determination of BAFF (B-cell-activating factor) serum levels among patients with CAT and GD obtained a lower mean value of BAFF for the CAT group compared with the GD group. The evolution of BAFF serum level related to the serum levels of the antithyroid antibodies ATPO (antithyroidperoxidase) and ATG (antithyroglobulin) was also analyzed. In the patients with GD, BAFF was not correlated with the value of ATPO or ATG, but in the patients with CAT, a correlation was found between the value of BAFF and the level of ATG but not the ATPO level. <b>Conclusions:</b> This study analyzed BAFF serum levels in patients with CAT and GD. The results indicate that BAFF acts as a stimulatory factor of immunoglobulin production in autoimmune diseases. These results require clarifying the role and therapeutic benefits of supplementing vitamin D intake in patients with autoimmune diseases.