Autoantibodies to 24 antigenes in various forms of tuberculosis and sarcoidosis on the background of vitamin d insufficiency

Abstract

The vitamin D deficiency is associated with several autoimmune and chronic inflammatory diseasessuch as tuberculosis (TB) and sarcoidosis (Sr). We studied blood samples taken in March - April in Saint Petersburg area (59° north latitude) from patients with different forms of pulmonary tuberculosis, sarcoidosis, and from healthy donors, distinguishing between tuberculosis patients with short either long duration of disease. We measured the levels of calcifediol and calcitriol, prolactin in sera, cathelicidin in plasma, and the individual autoimmune profile of patients. The level of 25(OH) D was low even in healthy adult donors - 19.3±1.4 ng/ml; however in all patients it was significantly lower. Active metabolite 1.25(OH)2 D3 concentration in serum was increased only in the sarcoidosis patients. During infection the activated macrophages convert the main circulating form 25(OH) D into the active 1.25 (OH)2 D3 which induces the antibacterial peptide cathelicidin. We saw no expected increase of cathelicidin levels in tuberculosis and sarcoidosis, apparently due to low concentration of 25 (OH) D. The prolactin content in the sarcoidosis patients did not differ from that of controls, but was significantly higher in patients with infiltrative and fibrous-cavernous tuberculosis. The individual mean immune reactivity level of autoantibodies to 24 antigens was significantly decreased in tuberculosis and sarcoidosis compared to healthy population, which indicates polyclonal immunosuppression in both diseases. Pronounced deviations from mean individual immune reactivity level were found for several antigens in all patients; the increase of the autoantibody production towards severalautoantigens could not be attributed to any clinical manifestation of comorbid autoimmune diseases in the corresponding organs. Hyperprolactinemia may contribute to autoimmune manifestations. We registered significant changes in the content of vitamin D, prolactin, and autoantibodies in pulmonary tuberculosis and sarcoidosis, as well as the difference between the studied groups of tuberculosis patients and failure of the cathelicidin response to infection in them