Lymphocyte changes in peripheral blood of metastatic non-small cell lung cancer patients receiving cryotherapy and immunotherapy

<bold>Background:</bold> Cryotherapy may offer a way to counteract cancer cell resistance to immunotherapy by inciting immune response in tumour microenvironment and helping neoantigen presentation. <bold>Aims and objectives:</bold> We aimed to evaluate the changes of lymphocytes and their subpopulations in response to cryotherapy and immunotherapy. <bold>Methods:</bold> Blood samples of 23 patients receiving first-line pembrolizumab immunotherapy, with or without platinum-based chemotherapy, were analyzed at baseline, before the second and third treatment cycles. 16 patients underwent bronchoscopic cryotherapy one week before systemic treatment. Lymphocyte counts were obtained from complete blood count tests. Flow cytometry was performed using anti- CD3, CD4, CD8, CD45, CD28 and Ki67 antibodies. Flow cytometry results are provided as median percentages of all lymphocytes. <bold>Results:</bold> The amount of lymphocytes significantly increased in the cryotherapy group before the second treatment cycle (1,8 vs 2,1 vs 2,0 x10⁹/l) and decreased in the control group at the time of the third cycle (1,8 vs 1,7 vs 1,3 x10⁹/l). The proportion of CD3+ T cells remained steady in the cryotherapy (70,8 vs 70,7 vs 71,2%) and control (72,1 vs 70,8 vs 69,0%) groups. The proportions of CD4+ and CD8+ T cells also remained unchanged in both groups. The proportion of CD8+ CD28+ Ki67+ T cells rose significantly in the cryotherapy group (0,6 vs 1,2 vs 1,3%). Meanwhile a statistically not significant increase was also observed in the control group (0,7 vs 1,4 vs 1,1%). <bold>Conclusion:</bold> Cryotherapy appears to help sustain the systemic lymphocyte response in non-small cell lung cancer patients receiving immunotherapy.