High levels of interleukin-6 are associated with low tumor burden and low growth fraction in multiple myeloma.
Interleukin-6 (IL-6) is a multifunctional cytokine postulated to play a central role as a growth factor for multiple myeloma (MM). We evaluated the spontaneous secretion of IL-6 in supernatants of Ficoll-Hypaque--enriched bone marrow (BM) cultures from 35 patients with MM. The levels of IL-6 were correlated with biological and clinical characteristics of the disease. High levels of IL-6 production defined a subgroup of patients with low tumor burden as determined by lower serum beta 2-microglobulin (B2M) (P = .02) and lower percentage of myeloma cells infiltrating the bone marrow (P = .003), higher synthetic rates of monoclonal protein (P = .006), and low proliferative compartments as measured by the percentage of Ki-67--positive myeloma cells. Patients with high proliferative fractions (Ki-67--positive myeloma cells > 20%) had significantly lower levels of IL-6 when compared with patients with low proliferative fractions (P = .005). Our findings do not support IL-6 as a major growth factor for MM, but demonstrate an association of high levels of IL-6 secretion with low tumor cell burden and low proliferative fraction.
Ballester
O F
OF
Division of Bone Marrow Transplantation, H. Lee Moffitt Cancer Center, Tampa, FL 33612-9497.
Moscinski
L C
LC
Lyman
G H
GH
Chaney
J V
JV
Saba
H I
HI
Spiers
A S
AS
Klein
C
C
D000368:Aged; D000369:Aged, 80 and over; D002455:Cell Division; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D015996:Survival Rate; D014407:Tumor Cells, Cultured
D015850:Interleukin-6