There are many structures in the spleen called "blood sinuses". At ordinary times, part of the blood stays in the blood sinus. When the human body loses blood, the blood sinus contracts, releasing this part of blood to the periphery to replenish blood volume. A large number of macrophages are attached to the wall of blood sinus, which can devour aging red blood cells, pathogens and foreign bodies. Spleen Spleen is the largest immune organ in the body, accounting for 25% of the total lymphoid tissue. It contains a large number of lymphocytes and macrophages. It is the center of cellular immunity and humoral immunity, and plays an anti-tumor role through various mechanisms. Splenectomy leads to the disorder of cellular immunity and humoral immunity, which affects the occurrence and development of tumors.

After splenectomy, patients' immune function is low, and their lifelong susceptibility to severe infection is increased, and they are prone to acute fulminant infection (OPSI), septicemia and meningitis. Infants are more prone to infectious complications after splenectomy. Pay attention to prevent infection after splenectomy, including keeping warm, food hygiene, personal hygiene and proper exercise. Spleen is not the only immune organ. After a period of adjustment, the body's immunity can be restored to a certain extent, and some of its immune functions will be replaced by other immune organs. Of course, it is impossible to completely return to normal people.