Phenotypic analysis of prostate-infiltrating lymphocytes reveals TH17 and Treg skewing.
OBJECTIVE
Pathologic examination of prostate glands removed from patients with prostate cancer commonly reveals infiltrating CD4+ and CD8+ T cells. Little is known about the phenotype of these cells, despite accumulating evidence suggesting a potential role for chronic inflammation in the etiology of prostate cancer.


METHODS
We developed a technique that samples the majority of the peripheral prostate through serial needle aspirates. CD4+ prostate-infiltrating lymphocytes (PIL) were isolated using magnetic beads and analyzed for subset skewing using both flow cytometry and quantitative reverse transcription-PCR. The transcriptional profile of fluorescence-activated cell sorted prostate-infiltrating regulatory T cells (CD4+, CD25+, GITR+) was compared with naïve, peripheral blood T cells using microarray analysis.


RESULTS
CD4+ PIL showed a paucity of TH2 (interleukin-4-secreting) cells, a surprising finding given the generally accepted association of these cells with chronic, smoldering inflammation. Instead, CD4+ PIL seemed to be skewed towards a regulatory Treg phenotype (FoxP3+) as well as towards the TH17 phenotype (interleukin-17+). We also found that a preponderance of TH17-mediated inflammation was associated with a lower pathologic Gleason score. These protein level data were reflected at the message level, as analyzed by quantitative reverse transcription-PCR. Microarray analysis of pooled prostate-infiltrating T(reg) revealed expected Treg-associated transcripts (FoxP3, CTLA-4, GITR, LAG-3) as well as a number of unique cell surface markers that may serve as additional Treg markers.


CONCLUSIONS
Taken together, these data suggest that TH17 and/or Treg CD4+ T cells (rather than TH2 T cells) may be involved in the development or progression of prostate cancer.
Department of Urology, James Buchanan Brady Urological Institute, MD, USA.
Karen Sandell
KS
Sfanos
Tullia C
TC
Bruno
Charles H
CH
Maris
Lauren
L
Xu
Christopher J
CJ
Thoburn
Angelo M
AM
DeMarzo
Alan K
AK
Meeker
William B
WB
Isaacs
Charles G
CG
Drake
D000328:Adult; D000368:Aged; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011471:Prostatic Neoplasms / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014158:Transcription, Genetic