Activation and dramatically increased cytolytic activity of tumor specific T lymphocytes after radio-frequency ablation in patients with hepatocellular carcinoma and colorectal liver metastases.
OBJECTIVE
To assess if a specific cytotoxic T cell response can be induced in patients with malignant liver tumors treated with radio-frequency ablation (RFA).


METHODS
Six Patients with liver metastases of colorectal cancer and 6 with hepatocellular carcinoma (HCC) underwent RFA. Blood was sampled before, 4 and 8 wk after RFA. Test antigens were autologous liver and tumor lysate obtained from each patient by biopsy. Peripheral T cell activation was assessed by an interferon gamma (IFNgamma) secretion assay and flow cytometry. T cells were double-stained for CD4/CD8 and IFNgamma to detect cytotoxic T cells. The ratio of IFNgamma positive and IFNgamma negative T cells was determined as the stimulation index (SI). To assess cytolytic activity, T cells were co-incubated with human CaCo colorectal cancer and HepG2 HCC cells and release of cytosolic adenylate kinase was measured by a luciferase assay.


RESULTS
Before RFA SI was 0.021 (+/- 0.006) for CD4(+) and 0.022 (+/- 0.004) for CD8(+) T cells against nonmalignant liver tissue and 0.018 (+/- 0.005) for CD4(+) and 0.021 (+/- 0.004) for CD8(+) cells against autologous tumor tissue. Four weeks after RFA SI against tumor tissue increased to 0.109 (+/- 0.005) for CD4(+) and 0.11 (+/- 0.012) for CD8(+) T cells against HCC, and to 0.115 (+/- 0.031) for CD4(+) and 0.15 (+/- 0.02) for CD8(+) cells for colorectal metastases (P < 0.0001). No increased SI was observed with nonmalignant tumor tissue at all time points. Before RFA cytolytic activity against the respective cancer cells was low with 2.62 (+/- 0.37) relative luminescence units (RLU), but rose more than 100 fold 4 and 8 wk after RFA. Spontaneous release was < 2% of maximum release in all experiments.


CONCLUSIONS
Patients with primary and secondary tumors of the liver show a significant tumor-specific cytotoxic T-cell stimulation with a dramatically increased tumor specific cytolytic activity of CD8(+) T cells after RFA.
Hansler
Johannes
J
Department of Medicine, Friedrich Alexander University, Erlangen Nuremberg, Germany.
Wissniowski
Thaddaus-Till
TT
Schuppan
Detlef
D
Witte
Astrid
A
Bernatik
Thomas
T
Hahn
Eckhart-Georg
EG
Strobel
Deike
D
D000263:Adenylate Kinase / Q000032:analysis; D000368:Aged; D000369:Aged, 80 and over; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000502:physiology*; D006528:Carcinoma, Hepatocellular / Q000276:immunology* / Q000601:surgery*; D017115:Catheter Ablation; D018920:Coculture Techniques; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis / Q000502:physiology; D008113:Liver Neoplasms / Q000276:immunology* / Q000556:secondary / Q000601:surgery*; D008213:Lymphocyte Activation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009336:Necrosis / Q000473:pathology; D009362:Neoplasm Metastasis / Q000473:pathology / Q000503:physiopathology; D014407:Tumor Cells, Cultured
D007371:Interferon-gamma; D000263:Adenylate Kinase