Complement receptor 2 and autoimmunity

Abstract

Complement receptor 2 (CR2/CD21) plays a major role in the immune response by linking innate and adaptive immunity to foreign pathogens and proteins. In addition, several lines of evidence strongly support a role for CR2 in the maintenance of tolerance to self-antigens. Both the absence of CR2 expression (along with the alternatively spliced gene product CR1) and the presence of a dysfunctional CR2 protein are tightly associated with the development of autoreactivity to nuclear antigens. Altered levels of expression of CR2 in patients with systemic lupus erythematosus support a clinically relevant role for this phenotype. Several possible mechanisms could underlie the loss of self-tolerance related to CR2, but the effect is most likely related to the failure of one or more specific checkpoints that limit autoreactivity during B cell development and immune reactions.

Key Biomarkers