Article
Tumor-reactive T-cells in the peripheral blood and differential T-cell infiltration of the tumor in patients with HNSCC
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Published: | August 8, 2007 |
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Tumor infiltration by CD 8 T-cells can lead to tumor cell apoptosis and necrosis. Regulatory CD 4 T-cells however can suppress cellular anti-tumor immune response. The relation to tumor reactive T-cells in the peripheral blood of patients with HNSCC is still unclear.
In 66 patients with HNSCC T-cells were isolated preoperatively from the peripheral blood and tested for tumor reactivity by Interferon-gamma-ELISPOT assay since 2000. The findings were correlated as well with the tumor infiltration by CD3, CD4 and CD8 T-cells assessed by immunohistochemistry as the clinical outcome.
As to CD3 and CD8 T-cell infiltration there was no significant difference for patients with (PB+) and without (PB-) tumor reactive T-cells in the peripheral blood. As to CD4 cells, however, there were significantly less cells for PB+ (9 [± 10]) in comparison to PB- (57 [±54] (p=0.04)). The CD4/CD8 ratio was significantly lower for PB+ than for PB- (p<0.05). For patients with UICC stage IV (n=46) there was a progression free survival time (regarding a period of observation of 2 months to 5 years) of 73% for PB+ in comparison to 59% for PB- (statistically not significant).
Patients with spontaneous tumor reactive T-cells in the peripheral blood show a significantly more favourable ratio of CD8 killer cells to CD4 T-cells and a lower rate of relapse. In case these results can be confirmed in a greater number of patients tumor reactive T-cells might be a favourable prognostic marker in patients with HNSCC. An effective immunotherapy may be reached by enhancing the natural tumor immunicity by inhibition of regulatory CD4 T-cells and/or activation of CD8 killer cells.