Cell-bound complement activation products (CB-CAPs) are biomarkers for a lupus diagnosis.
C4d has been identified on surfaces of normal erythrocytes, T and B lymphocytes, and reticulocytes.
Patients with SLE have substantially higher levels of erythrocyte-bound, lymphocyte bound, platelet-bound, and reticulocyte-bound complement activated products than healthy individuals or patients with other inflammatory, autoimmune, and rheumatologic diseases.
The Avise SLE 2.0 diagnostic uses cell-bound complement activation products (CB-CAPs) technology, specifically the EC4d and BC4d markers.
Cell-Bound Complement Activation Products (CB-CAPs) are hydrolyzed complement activation products bound to circulating cells such as erythrocytes, platelets, B and T lymphocytes.
Such binding confers stability to these markers because they last for the life of the cells.
There is also a correlation between the quantification of CB-CAPs and the degree of complement activation, making CB-CAPs ideally suited as biomarkers of SLE.