The top ten clues to understand the origin of chronic lymphocytic leukemia (CLL)

Abstract

The fundamental task of the immune system is to protect the individual from infectious organisms without serious injury to self. The essence of acquired immunity is molecular self/non self discrimination. Chronic lymphocytic leukemia is characterized by a global failure of immune system that begins with the failure of immunological tolerance mechanisms (autoimmunity) and finish with the incapacity to response to non-self antigens (immunodeficiency). Immunological tolerance mechanisms are involved in chronic lymphocytic leukemia (CLL) development. During B cell development some self-reactive B cells acquire a special BCR that recognize their own BCR. This self-autoantibody-self BCR interaction promotes survival, differentiation and proliferation of self-reactive B cells. Continuous self-autoantibody-self BCR interaction cross-linking induces an increased rate of surface BCR elimination, CD5+ expression, receptor editing and anergy. Unfortunately, some times this mechanisms increase genomic instability and promote additional genetic damage that immortalize self-reactive B cells and convert them into CLL like clones with the capability of clonal evolution and transformed CLL B cells. This review summarizes the immunological effects of continuous self-autoantibody-self BCR interaction cross-linking in the surface of self-reactive B cells and their role in CLL development.