Under B- celle modning viser CD20 sig først i mellemstadiet af B- lymfoblast (præ- B- celle) og forsvinder under slutstadiet af B- cellernes modning til plasmaceller.
During B-cell maturation, CD20 is first expressed in the midstage of B-lymphoblast (pre-B-cell), and is lost during the final stage of B-cell maturation to plasma cells.