Impact of radiofrequency ablation on PBMC subpopulation in patients with renal cell carcinoma☆

Abstract 

Purpose

With the development of diagnostic techniques, renal cell carcinoma (RCC) is currently diagnosed in earlier stages, allowing the introduction of less invasive techniques in its management. One of the most promising new treatment methods is based on the utilization of high temperature created by radiofrequency current circulating around the needle probe introduced into the tumor. Besides the direct destruction of the cancer tissue, the treatment may induce immunologic reaction to tumor antigens released from destroyed tumor cell. This paper describes changes observed in the peripheral blood lymphocyte population after radiofrequency ablation (RFA) of RCC.

Methods

Blood was tested before, and 2, 4, and 6 weeks after the RFA in 6 patients with RCC for the proportions and numbers of CD3⁺, CD3⁺HLA-DR⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, and CD56⁺CD16⁺ cells. The blood was stained with fluorochrome-conjugated monoclonal antibodies and percentages of cells expressing various markers were determined by flow cytometry.

Results

In all patients, the changes were most pronounced 2 weeks after the procedure. The proportion of CD4⁺ and CD8⁺ lymphocytes were changed. In 1 patient, an increase in both CD4⁺ and CD8⁺ cells was observed. In 5 out of 6 patients, the proportion of activated (DR⁺) cells was increased over the whole follow-up period with the highest values in the second week after RFA. The percentage of the CD56⁺CD16⁺ was decreased in most of the patients.

Conclusions

Our study confirms that in the majority of patients, RFA of the renal tumors causes significant changes in the proportion of the peripheral immune cells. We suggest that the results presented in this article shows the necessity for further studies.

Keywords: Radiofrequency ablation, Renal cell carcinoma, Tumor antigens, Lymphocytes activation, Immunotherapy