CD20 or B-lymphocyte antigen CD20 is a non-glycosylated phosphoprotein which is expressed on the surface of mature naive B cells. In humans, CD20 is encoded by the gene, membrane spanning 4-domains A1 (MS4A1). Diseases associated with this gene include immunodeficiency and common variable. The related pathways among CD20 are B cell development pathways, together with hematopoietic stem cell differentiation pathways and lineage-specific markers. CD20 is membrane-embedded surface molecule with about 33-37 kDa and plays a key role in the development and differentiation of B-cells into plasma cells. It is also important for the regulation of intracellular calcium involved in transmembrane calcium influx. Measuring CD20 antigen on blood cells may aid to diagnose cancer so that it is considered as a type of tumor marker. CD22 (Cluster of differentiation 22), also referred to SIGLEC2 or B-cell receptor CD22, is a 135-140 kDa transmembrane glycoprotein and a member of the SIGLEC family of lectins. The protein encoded by this gene is localized at the chromosome 19q13.12 and codes for alternative spliced forms including CD22, CD22α, and CD22β. of which the latter is the predominant species expressed by B cells. The expression of CD22 is restricted to the cytoplasm of pre-B cells and progenitor in the early B-cell development. CD22 serves as a cell adhesion receptor for sialic acid-bearing ligands which is expressed on erythrocytes and all leukocytes. Additionally, CD22-mediated signal transduction can activate B cells and modulate antigen receptor signaling in vitro.