Plasma exchange is a method of using equipment (machine and filter), taking blood out and separating the plasma containing pathogenic factors from the blood cells. The deficient plasma is supplemented with donor plasma or plasma substitute. Plasma exchange is applied in the treatment of diseases related to autoantibodies, or antigen-antibody complexes circulating in the blood.

Dermatomyositis is a disease with muscle inflammation accompanied or not by skin lesions. Polymyositis is an autoimmune disease and responds to immunosuppressive drugs. The disease can appear at any age, usually in adolescence (10-15 years old) and middle age (45-60 years old), women are more affected than men. The incidence of polymyositis in the community is estimated at 5-10 cases/1 million people.

Myasthenia Gravis is a chronic neuromuscular disease characterized by muscle weakness occurring intermittently or continuously with varying degrees of severity.

Plasma exchange is a therapy that removes a certain amount of plasma from a patient's blood and replaces it with a similar amount of plasma. The blood is drained through a filtration system, where a certain amount of plasma is removed and replaced with an equivalent amount of plasma or albumin, and the blood is then returned to the body.