Activation of the complement system.
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000276:immunology; D003167:Complement Activation; D003175:Complement C2 / Q000096:biosynthesis; D003179:Complement C3b / Q000096:biosynthesis; D003181:Complement C4 / Q000096:biosynthesis; D003171:Complement Pathway, Classical; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis
D003175:Complement C2; D003181:Complement C4; D007136:Immunoglobulins; D003179:Complement C3b