Fc gamma receptors in autoimmune diseases

Fc gamma -receptors (Fc gamma -R) recognise the Fc portion of IgG and thus form a link between humoral and cellular immunity. These receptors are expr essed by a variety of immune cells, and they function in the binding of imm une complexes or IgG-opsonised particles, such as microbial pathogens. The are three major types of Fc gamma -R, namely Fc gamma -RI (CD64), Fc gamma -RII (CD32) and Fc gamma -RIII (CD 16), and these differ in their ability t o bind IgG and complexes. There are many isoforms of these receptors and a number of recently identified polymorphisms in their structure. This review describes the structure and function of these Fc gamma -Rs, and highlights how gene deficiencies and polymorphisms may contribute to the pathology of human diseases.