BTK and B-cell chronic lymphocytic leukemia: Stereotypic CLL#5 BCR (IGHV1–69, IGHD3–10/3–3, IGHJ6, 20 amino acids HCDR3) as well as stereotypic CLL#64 BCR (IGHV3 subgroup genes, IGHD2 subgroup genes, IGHJ6, 21 amino acids HCDR3) [17] were relatively often detected in naive mature B cells of especially individuals 70 + y.