The Aim of this work was to study the functional activity of monocytes, neutrophils and cytokines in twin children with Inflammatory diseases of the paranasal sinuses in comparison with non-twins. It was found that with various rhinosinusitis in children, phagocytic activity of monocytes in blood decrease, which causes the development of a chronic purulent focus and is characterized by an increase in monocytes with viral inclusions. In patients with Inflammatory diseases of the paranasal sinuses, the activity of non-specific protective factors of the body is significantly reduced, which is expressed in a decrease phagocytic activity of monocytes and an increase monocyte with viral inclusions, which is more evidently in twin children than in non-twin children. Serum cytokines in children with Inflammatory diseases of the paranasal sinuses were significantly increased in relation to the data of healthy children. In children-twins and non - twins, the parameters of anti-inflammatory cytokines changed in different directions.
