title: Infections and hypocomplementemia.
abstract: The complement system, phagocytic leukocytes, and antibodies constitute the "department of defense" in the battle against infections caused by pyogenic microorganisms. Complement components are capable of directly killing (by lysis) certain susceptible bacteria and are the source of chemotactic peptides and heat-labile opsonin, which facilitate recognition and killing of microbes by phagocytic cells. When these vital functions are compromised, as in individuals with inherited deficiencies of complement components, the result is unusual susceptibility to severe infections.
mesh_terms: D003167:Complement Activation; D003175:Complement C2 / Q000172:deficiency; D003179:Complement C3b / Q000032:analysis; D003182:Complement C5 / Q000172:deficiency; D003165:Complement System Proteins / Q000032:analysis / Q000172:deficiency* / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D007239:Infections / Q000276:immunology*
chemical_list: D003175:Complement C2; D003182:Complement C5; D003179:Complement C3b; D003165:Complement System Proteins