Immune Cell Profiling of Peripheral Blood in Long-Term Testicular Germ Cell Tumor Survivors

Kristína Kilíková¹Andrea Mlčáková²Zuzana Šestáková³Katarina Kalavska²Kristýna Adámiková²Jana Obertová²Patrik Palacka^2,4Katarina Rejlekova^1,2Zuzana Syčová-Milá²Valentina De Angelis²Zuzana Országhová²Peter Lesko²Daniela Svetlovská²Beata Mladosievicova¹Liang Cheng⁵Michal Mego^1,2Michal Chovanec^1,2,4*

• ¹Univerzita Komenskeho v Bratislave Lekarska fakulta, Bratislava, Slovakia
• ²Narodny onkologicky ustav, Bratislava, Slovakia
• ³Narodny ustav detskych chorob, Bratislava, Slovakia
• ⁴Slovenska akademia vied, Bratislava, Slovakia
• ⁵Brown University Warren Alpert Medical School, Providence, United States

Abstract Introduction: This study addresses changes in peripheral blood immune cell composition and possible late effects of curative treatment in testicular germ cell tumors (GCT) survivors. Methods: We analyzed the immunophenotype in peripheral blood obtained from 202 survivors treated at the National Cancer Institute in Bratislava by flow cytometry. The median long-term follow-up was 13 years (1-35). We divided the survivors into groups as follows: CT-chemotherapy (N=141), RT-radiotherapy (N=16), CTRT – chemotherapy + radiotherapy (N=13), and the control group of patients under active surveillance - AS (N=32). Results: Survivors treated with AS had a lower number of B-cells (mean ± standard deviation (SD) = 10.3±3.5 vs 11.9±4.2, p=0.04) compared to the CT group. Survivors treated with AS vs RT had a higher number of total lymphocytes (29.8±7.7 vs 25.2±6.3, p=0.04). In AS vs CTRT group B-cells (10.3±3.5 vs 13.7±5, p=0.01) and conventional dendritic cells (cDCs) (74.3±11.8 vs 82.5±6.7, p=0.04) showed lower numbers. Survivors treated with AS vs. ≤ 400 mg/m2 cumulative dose of cisplatin had fewer eosinophils (2.29±1.5 vs 2.99±1.7, p=0.03) and double-negative T-cells (DNT cells) (4.7±3.4 vs 6.6±6.6, p=0.04). In AS vs. ≥ 400 mg/m2, B cells counts were lower in the control group (10.96±5.3 vs 12.3±4.8, p=0.03); treatment with ≤ 400 mg/m2 vs. ≥ 400 mg/m2 resulted in higher counts of eosinophils (3.0±1.7 vs 2.1±1.7, p=0.00025) and DNT cells (6.7±6.7 vs 4.9±3.6, p=0.02). Conclusions: Our study demonstrates an association between both cisplatin-based chemotherapy and radiotherapy with specific immune cell populations, suggesting that these treatment modalities may exert long-term immunomodulatory effects.