Introduction: Head and neck cancer is the seventh most common cancer worldwide. In inoperable cases, primary radiochemotherapy is another treatment option left for head and neck squamous cell carcinoma (HNSCC) patients. Changes induced by RCT in immune cell homeostasis are of great interest as they might interfere with anti-tumor activity. Herein, we compared the composition of major lymphocyte subsets in the peripheral blood of controls (n=22), and of non-relapse (n=31) and relapse (n=4) HNSCC patients before and after RCT.
Methods: EDTA blood of non-recurrent HNSCC patients was collected before RCT (t0), directly after RCT (t1) and in the follow-up period 3 (t2) and 6 months (t3) after RCT. In recurrent patients, blood samples were taken at t0, t1, t2 and at the time of recurrence (t5). The blood of healthy human volunteers served as a control. The composition of major lymphocyte subpopulations was phenotyped by multiparameter flow cytometry.
Results: Non-relapse HNSCC patients had significantly lower proportions of CD19+ B-cells compared to healthy individuals already before initiation of any therapy (t0). B-cell counts dropped further until 3 months after RCT (t2) but reached initial levels 6 months after RCT (t3). In non-recurrent patients, the proportion of CD3+ T and CD3+/CD4+ T-helper-cells continuously decreased between t0 and t3, while that of CD8+ cytotoxic T-cells and CD3+/CD56+ NK-like T-cells (NKT) gradually increased in the same period of time. The percentage of CD4+/FoxP3+ regulatory T-cells (Tregs) dropped directly after RCT, but increased above initial levels in the follow-up period 3 (t2) and 6 (t3) months after RCT. At t0, non-recurrent patients had almost twice as much of CD56bright/CD16+ NK-cells as controls, which dropped significantly at t1. Relapse patients presented similar trends with respect to the percentages of B, T-cells and Tregs between t0 and t5, however, due to the small number of patients the data did not reach statistical significance. Compared to non-recurrent patients, CD4+ T-cells of recurrent patents appear to remain stably low, particularly at t0. The percentages of CD8+ cytotoxic T-cells und CD3+/CD56+ NKT-cells in relapse patients were higher than those in non-relapse patients, but they remained nearly unaltered over the course of RCT. While all NK cell subsets (CD3-/CD56+, CD56+/CD69+, CD3-/CD94+, CD3-/NKG2D+, CD3-/NKp30+, CD3-/NKp46+) increased continuously up to 6 months after RCT (t0-t3) in non-relapse patients, they remained stably low up to 3 months (t2) after RCT in relapse patients.
Conclusion: Non-relapse and relapse HNSCC patients, treated with primary RCT, have altered lymphocyte homeostasis, which already exists before start of therapy and persists for months in the follow-up period. Thus, monitoring the kinetics of lymphocyte subsets during RCT might provide a clue for the development of an early relapse, offer early evaluation of treatment outcome or might even help in the selection of patients that might profit from an additional immunotherapy.
«
Introduction: Head and neck cancer is the seventh most common cancer worldwide. In inoperable cases, primary radiochemotherapy is another treatment option left for head and neck squamous cell carcinoma (HNSCC) patients. Changes induced by RCT in immune cell homeostasis are of great interest as they might interfere with anti-tumor activity. Herein, we compared the composition of major lymphocyte subsets in the peripheral blood of controls (n=22), and of non-relapse (n=31) and relapse (n=4) HNSCC...
»