Test Details: CD19 is a type I transmembrane glycoprotein, expressed on virtually all B cells with the exception of plasma cells and is also found on follicular dendritic cells. CD19 has an essential regulatory role in B cell differentiation, proliferation and subsequent antibody production. It acts as an adaptor protein to recruit cytoplasmic signaling proteins to the membrane. Due to its presence on all B cells, it is a biomarker for B lymphocyte development, lymphoma diagnosis, identification between normal and neoplastic B cells and can be utilized as a target for leukaemia immunotherapies.