CD19 and B-cell chronic lymphocytic leukemia: Domizi et al. demonstrated that knock-down of IKZF1 in LCBL and CLL cell lines (respectively, OCI-Ly1, OCI-Ly7, SUDHL6; CI, JVM-2, WA-OSEL) is associated with reduced CD19 surface expression, as measured through flow cytometry, possibly leading to CD19-negative relapses [55].