Excessive production of transforming growth factor-beta by bone marrow stromal cells in B-cell chronic lymphocytic leukemia inhibits growth of hematopoietic precursors and interleukin-6 production.
To explore the pathogenesis of marrow failure in B-cell type chronic lymphocytic leukemia (B-CLL), we have examined the production of interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage CSF (GM-CSF) by the adherent cell population of bone marrow (BM) derived from B-CLL patients and their capacity to support hematopoietic cell proliferation. Lipopolysaccharide-stimulated B-CLL stromal cells produced G-CSF and GM-CSF in amounts similar to normal stromal layers, whereas IL-6 production was significantly decreased. Using the blast-colony forming cell assay (BI-CFC) and the classical colony-forming unit granulocyte macrophage (CFU-GM) assay, we found that: (1) marrow stromal cells of B-CLL were able to support only 25% of the BI-CFC growth supported by normal marrow stromal cells; (2) this anomaly was partially corrected by the addition of exogenous IL-6; (3) the colony-stimulating activity (CSA) of the conditioned medium (CM) of B-CLL stromal cells was lower than that of normal CM; (4) that this was the result of the presence of an inhibitor rather that of a growth factor defect; (5) this inhibition could be abrogated by addition of anti-transforming growth factor-beta (TGF-beta) neutralizing antibody; (6) this antibody corrected the deficient colony supportive activity of the B-CLL stromal cells; (7) TGF-beta production by marrow stromal cells was significantly increased in CLL compared with normal; and (8) that this was not caused by the effect of the B-CLL lymphocytes on the stromal cells. It is concluded that this increased TGF-beta production in B-CLL is probably responsible for the decreased IL-6 production by stromal cells and for the inhibiting activity on hematopoietic precursors as well. We hypothesize that TGF-beta generated at a high level by B-CLL marrow stromal cells could play a major role in the pathophysiology of the BM failure seen in advanced stages of B-CLL.
Lagneaux
L
L
Service de Médecine Interne, Institut J. Bordet, Brussels, Belgium.
Delforge
A
A
Dorval
C
C
Bron
D
D
Stryckmans
P
P
D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000378:metabolism*; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D016179:Granulocyte Colony-Stimulating Factor / Q000096:biosynthesis; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000378:metabolism*; D008875:Middle Aged; D017154:Stromal Cells / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D015850:Interleukin-6; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor