👉 Polyserositis is a type of autoimmune disease that affects the lining of the gastrointestinal tract, causing inflammation and swelling. It can cause symptoms such as diarrhea, abdominal pain, and nausea, and it can also affect other organs in the body, including the lungs, kidneys, and eyes. The exact causes of polyserositis are not fully understood, but some theories suggest that it may be caused by an autoimmune response to a harmless substance called a polybasic antigen.