In vivo dynamics of stable chronic lymphocytic leukemia inversely correlate with somatic hypermutation levels and suggest no major leukemic turnover in bone marrow.
Although accumulating evidence indicates that chronic lymphocytic leukemia (CLL) is a disease with appreciable cell dynamics, it remains uncertain whether this also applies to patients with stable disease. In this study, (2)H(2)O was administered to a clinically homogeneous cohort of nine stable, untreated CLL patients. CLL dynamics in blood and bone marrow were determined and compared with normal B-cell dynamics in blood from five healthy individuals who underwent a similar (2)H(2)O labeling protocol. Average CLL turnover rates (0.08-0.35% of the clone per day) were approximately 2-fold lower than average B-cell turnover rates from healthy individuals (0.34-0.89%), whereas the rate at which labeled CLL cells in blood disappeared (0.00-0.39% of B cells per day) was approximately 10-fold lower compared with labeled B cells from healthy individuals (1.57-4.24% per day). Leukemic cell turnover variables inversely correlated with the level of somatic hypermutation of the CLL clone (IgVH mutations). Although CLL cells in bone marrow had a higher level of label enrichment than CLL cells in blood, no difference between proliferation rates and proapoptotic and antiapoptotic profiles of CLL cells from these compartments was observed. These data suggest that, in stable disease, there is a biological relationship between the degree of somatic hypermutation of the CLL clone and its dynamics in vivo. Furthermore, in contrast to lymph nodes, the bone marrow does not seem to be a major CLL proliferation site.
van Gent
Rogier
R
Department of Immunology, University Medical Center Utrecht, Utrecht, the Netherlands.
Kater
Arnon P
AP
Otto
Sigrid A
SA
Jaspers
A
A
Borghans
José A M
JA
Vrisekoop
Nienke
N
Ackermans
Mariëtte A T
MA
Ruiter
An F C
AF
Wittebol
Shulamiet
S
Eldering
Eric
E
van Oers
Marinus H J
MH
Tesselaar
Kiki
K
Kersten
Marie José
MJ
Miedema
Frank
F
D017209:Apoptosis / Q000235:genetics; D001853:Bone Marrow / Q000473:pathology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007223:Infant; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood / Q000235:genetics* / Q000473:pathology*; D008297:Male; D009154:Mutation; D012334:RNA, Neoplasm / Q000235:genetics
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D012334:RNA, Neoplasm