Finally, 20–25% of CLL cases are characterized by the existence of stereotyped heavy chain complementarity determining region 3 (HCDR3) sequences within the functional heavy chain rearrangement which suggests the recognition of repetitive and shared antigenic epitopes in unrelated patients with CLL.(24) In contrast, stereotyped HCDR3 sequences are rarely present (<5%) among individuals with population-screening MBL, underscoring another biologic difference with frank CLL.(8)
