Human Complement C4 Protein

Background

Complement C4A (Chido/Rodgers blood group) is a component of the classical complement pathway, which plays a crucial role in immune defense and inflammation C4A is involved in the formation of the C3 convertase complex, which leads to the activation of the complement cascade, promoting opsonization, pathogen destruction, and inflammation The Chido and Rodgers antigens are variants of C4A that are of clinical interest due to their association with blood transfusion reactions and their use as markers in blood group systems Complement C4A, along with C4B, contributes to the body's ability to fight infections, clear immune complexes, and resolve inflammation Dysregulation of C4A has been implicated in autoimmune diseases, such as lupus, where complement activation exacerbates tissue damage and inflammation C4A also influences immune responses to cancer, where its role in immune complex clearance can impact tumor progression and metastasis Understanding C4A and its polymorphisms is crucial for improving clinical approaches to immune modulation and blood group testing