Structure and function of autoantibodies and their role in autoimmune rheumatic diseases

Autoantibodies bind to antigens present in the body itself. Antibody molecules consist of variable and constant regions, which have different functions. The constant regions have effector functions, such as complement fixation and Fc receptor activation. In autoimmune rheumatic diseases, autoantibodies with different constant regions play different roles in the disease process and this may help us to treat these diseases. Antibodies to different self-antigens are characteristic of different diseases and develop this self-reactivity owing to the sequences of their complementarity-determining regions. Analysis of complementarity-determining region sequences suggests that this self reactivity comes about through antigen-driven selection of mutations. By characterizing these mutations we can aim to define and target populations of pathogenic autoantibodies that cause autoimmune rheumatic diseases.