Prognostic value of plasma interleukin-6 levels in patients with chronic lymphocytic leukemia.
BACKGROUND
Interleukin 6 (IL-6) is a B-cell growth and differentiation factor, which may promote the growth of B-cell neoplasms. In chronic lymphocytic leukemia (CLL) patients, IL-6 plasma levels increased in a stage-dependent manner, suggesting that IL-6 may be a useful prognostic marker. The purpose of this study is to fully assess the prognostic value of IL-6 in CLL patients.


METHODS
We measured the plasma levels of IL-6 in 100 CLL patients using an enzyme-linked immunoassay method.


RESULTS
Increasing levels of IL-6 significantly correlated with patient age, severity of anemia, Rai stage, white cell count, and beta-2-microglobulin (beta-2M). Although CLL patients did not differ significantly from the normal controls in the median IL-6 plasma level (P = 0.38), patients with advanced diseases (defined by Rai stage III/IV or beta-2M > 3.5) had a significantly higher median IL-6 plasma level than the normal controls (P < 0.05). Furthermore, in patients with advanced diseases, Cox regression hazards model showed that a higher IL-6 level correlated with shorter survival (P = 0.0001). Using IL-6 level of 3 pg/mL as a cutoff, patients with low IL-6 levels had a significantly longer overall survival than those with high IL-6 levels (log rank test, P = 0.002). In patients with CD38-positive CLL, patients with high IL-6 levels (> 3 pg/mL) had significantly shorter survival (P = 0.03). To conclude, IL-6 is a particularly useful predictor for survival in CLL patients with advanced diseases.


CONCLUSIONS
Our findings suggest that patients with advanced-stage CLL as well as high IL-6 plasma levels may require aggressive therapeutic approaches and special consideration for experimental therapy.
Lai
Raymond
R
Department of Hematopathology, The University of Texas M. D. Anderson Cancer Center, Houston 77030-4095, USA.
O'Brien
Susan
S
Maushouri
Taghi
T
Rogers
Anna
A
Kantarjian
Hagop
H
Keating
Micheal
M
Albitar
Maher
M
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology*; D008297:Male; D008562:Membrane Glycoproteins; D008875:Middle Aged; D009244:NAD+ Nucleosidase / Q000032:analysis; D009367:Neoplasm Staging / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis
D015703:Antigens, CD; D000943:Antigens, Differentiation; D014408:Biomarkers, Tumor; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1