Background
CD19 is a type I transmembrane glycoprotein that functions as coreceptor for the B cell antigen receptor complex (BCR) on B cell lymphocytes, and plays a vital role in humoral immune response. CD19 is expressed throughout B cell development from pre-B-cell differentiation with expression persisting until terminal differentiation into plasma cells, and is commonly used as B cell lineage marker; CD19 is also found on most B cell malignancies including chronic lymphocytic leukemias (CLLs), B cell non- Hodgkin's lymphomas (NHLs), and more aggressive B-ALL, which lead to the rapid development of therapeutic antibodies and chimeric antigen receptor therapy.
