Tumor-related immunity in prostate cancer patients treated with human recombinant granulocyte monocyte-colony stimulating factor (GM-CSF).
BACKGROUND
Granulocyte monocyte-colony stimulating factor (GM-CSF) supports the survival, expansion, and differentiation of lymphoid and myeloid derived dendritic cells (DCs). We hypothesized that systemic therapy with GM-CSF in prostate cancer patients could augment prostate cancer-related immunity and induce clinical response.


METHODS
Eligible patients were randomly assigned to receive either 125 or 250 microg/m(2) GM-CSF subcutaneously three times a week until clinical progression. Prostate-specific antigen (PSA) T cell precursor frequencies were determined by a flow cytometric method.


RESULTS
We were able to show, for the first time, a statistically significant correlation between pre-treatment PSA level and PSA-specific CD4(+) T cell precursors and a trend between pre-treatment PSA level and PSA-specific CD8(+) T cell precursors (P<0.0001 and P=0.059, respectively).


CONCLUSIONS
These results suggest that existent immunity to PSA in prostate cancer patients may be a promising target for future immunotherapeutic approaches to prostate cancer.
Schwaab
Thomas
T
Uro-Oncology Group, Norris Cotton Cancer Center (NCCC) at Dartmouth-Hitchcock Medical Center (DHMC), NH, Lebanon.
Tretter
Christopher P G
CP
Gibson
Jennifer J
JJ
Cole
Bernard F
BF
Schned
Alan R
AR
Harris
Robert
R
Fisher
Jan L
JL
Crosby
Nancy
N
Stempkowski
Laura M
LM
Heaney
John A
JA
Ernstoff
Marc S
MS
D000368:Aged; D000369:Aged, 80 and over; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D004305:Dose-Response Relationship, Drug; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood / Q000276:immunology; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000276:immunology*; D011994:Recombinant Proteins
D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D017430:Prostate-Specific Antigen