Helper T cell 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 several circulating helper T cell populations 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. Flow cytometry was performed using anti- CD3, CD4, CD45, Tbet, GATA3, RORγt and FOXP3 antibodies. Results are provided as median percentages of all CD4+ T cells. <bold>Results:</bold> In the cryotherapy group, the proportion of CD4+ Tbet+ (Th1) T cells was similar at all time points (9,1 vs 6,1 vs 9,5%), but decreased significantly in the control group (10,3 vs 7,2 vs 6,8%). The proportion of CD4+ GATA3+ (Th2) T cells decreased significantly in the cryotherapy group (30,2 vs 21,1 vs 21,9%), and remained similar in the control group (28,4 vs 32,5 vs 22,9%). The populations of CD4+ RORγt+ (Th17) T cells was stable in both the cryotherapy (4,8 vs 3,6 vs 4,4%) and control (3,5 vs 2,9 vs 5,1%) groups. Meanwhile, the CD4+ FOXP3+ (Treg) T cell population decreased significantly in the cryotherapy group (8,4 vs 6,6 vs 4,7%) and did not change for controls (6,1 vs 7,3 vs 7,8%). <bold>Conclusion:</bold> Cryotherapy appears to maintain the systemic anti-tumour Th1 response, while diminishing Th2 and Treg populations, in non-small cell lung cancer patients receiving immunotherapy.