Detection and functional analysis of tumor infiltrating T-lymphocytes (TIL) in liver metastases from colorectal cancer.
BACKGROUND
Tumor-infiltrating T lymphocytes (TIL) play an important role in primary colorectal cancer, but their activity in liver metastases has not yet been investigated. The aim of this study was to examine whether tumor-selective infiltration, activation, and cytotoxic activity of TIL can be demonstrated in situ in colorectal liver metastases.


METHODS
TIL were obtained from liver metastases and corresponding normal liver tissue of 16 patients with colorectal liver metastases. Characterization of TIL in situ was performed by multicolor flowcytometric analysis. Presence of tumor antigen-reactive T cells was evaluated by interferon gamma Elispot analysis.


RESULTS
TIL in colorectal liver metastases responding against tumor antigens were present in most patients. Although the proportions of CD3(+) T cells were comparable in liver metastasis and normal liver tissue, metastases contained significantly enhanced proportions of CD4(+) cells (49% vs. 22%, P < .001). Among all CD4(+) T helper cells, the proportion of activated (CD4(+)CD25(+)) effector cells was significantly increased in liver metastases (15.0% vs. 7.8%, P = .003). Metastases showed significantly higher proportions of activated (CD69(+) [70.1% vs. 49.8%, P = .02] and CD25(+) [4.1% vs. .6%, P = .06]) and cytotoxically active (CD107a(+)) CD8(+) TIL (3.2% vs. 1.3%, P = .03). Importantly, the presence of activated T helper cells correlated with the frequencies of cytotoxic T lymphocytes that exerted cytotoxic activity in situ (P = .02).


CONCLUSIONS
CD4(+) and CD8(+) TIL are selectively activated in liver metastases, and cytotoxic T lymphocytes exert tumor-selective cytotoxic activity in situ in the presence of activated T helper cells, suggesting the requirement of in-situ-activated T helper cells for efficient cytotoxic T lymphocytes effector function.
Department of Surgery, University of Heidelberg, INF 110, 69120 Heidelberg, Germany.
Philipp
P
Wagner
Moritz
M
Koch
Daniel
D
Nummer
Sylvia
S
Palm
Luis
L
Galindo
Daniel
D
Autenrieth
Nuh
N
Rahbari
Friedrich H
FH
Schmitz-Winnenthal
Volker
V
Schirrmacher
Markus W
MW
Büchler
Philipp
P
Beckhove
Jürgen
J
Weitz
D000230:Adenocarcinoma / Q000276:immunology / Q000473:pathology*; D015703:Antigens, CD / Q000276:immunology; D015179:Colorectal Neoplasms / Q000276:immunology / Q000473:pathology*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000276:immunology / Q000556:secondary*; D016246:Lymphocytes, Tumor-Infiltrating; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets; D006377:T-Lymphocytes, Helper-Inducer
D015703:Antigens, CD