Changes in peripheral blood T-cell balance after percutaneous tumor ablation.

PURPOSE: To evaluate the changes in T-cell balance in peripheral blood following percutaneous tumor ablation. MATERIAL AND METHODS: Patients underwent thermal ablation including radiofrequency (n = 9) and microwave ablation (n = 5), or cryoablation (n = 5). Target tumors were located in the lung (n = 7), soft tissue (n = 5), liver (n = 4), and bone (n = 3). Patient peripheral blood samples were collected before and within 14 days after ablation. Peripheral blood populations of cytotoxic T-cells (CTL), type-1 (Th1) and type-2 helper T-cells (Th2), and regulatory T-cells (Treg) were measured using flow cytometry. Changes in CTL/Treg and Th1/Th2 ratios before and after ablation therapy were compared using paired t-tests. RESULTS: Peripheral blood CTL population (27.5 ± 2.1% to 30.2 ± 2.5%, p < .03) and CTL/Treg ratios (18.8 ± 3.7% to 21.6 ± 3.6%, p < .05) increased significantly after ablation. Although a significant increase in CTL/Treg ratios was found after heat-based ablation (18.0 ± 4.4% to 21.6 ± 4.7%, p < .02), it remained unchanged after cryoablation (21.0 ± 7.0% to 21.5 ± 4.3%, p = .92). Th1/Th2 ratio (13.7 ± 3.0% to 17.2 ± 3.5%, p = .12) remained unchanged after ablation. CONCLUSION: Ablation therapy alters the T-cell balance by increasing the systemic CTL/Treg, ratio. Heat-based ablation might be a more effective approach than cryoablation to enhance systemic anti-tumor immunity.

Image-guided thermal ablation of tumors increases the plasma level of interleukin-6 and interleukin-10.

PURPOSE: To identify changes in plasma cytokine levels after image-guided thermal ablation of human tumors and to identify the factors that independently predict changes in plasma cytokine levels. MATERIALS AND METHODS: Whole-blood samples were collected from 36 patients at three time points: before ablation, after ablation (within 48 hours), and at follow-up (1-5 weeks after ablation). Plasma levels of interleukin (IL)-1α, IL-2, IL-6, IL-10, and tumor necrosis factor (TNF)-α were measured using a multiplex immunoassay. Univariate and multivariate analyses were performed using cytokine level as the dependent variable and sample collection, time, age, sex, primary diagnosis, metastatic status, ablation site, and ablation type as the independent variables. RESULTS: There was a significant increase in the plasma level of IL-6 after ablation compared with before ablation (9.6-fold ± 31-fold, P<.002). IL-10 also showed a significant increase after ablation (1.9-fold ± 2.8-fold, P<.02). Plasma levels of IL-1α, IL-2, and TNF-α were not significantly changed after ablation. Cryoablation resulted in the largest change in IL-6 level (>54-fold), whereas radiofrequency ablation and microwave ablation showed 3.6-fold and 3.4-fold changes, respectively. Ablation of melanomas showed the largest change in IL-6 48 hours after ablation (92×), followed by ablation of kidney (26×), liver (8×), and lung (6×) cancers. Multivariate analysis revealed that ablation type (P<.0003) and primary diagnosis (P<.03) were independent predictors of changes to IL-6 after ablation. Age was the only independent predictor of IL-10 levels after ablation (P< .019). CONCLUSIONS: Image-guided thermal ablation of tumors increases plasma levels of IL-6 and IL-10, without increasing plasma levels of IL-1α, IL-2, or TNF-α.