PD-1/TIGIT CD4⁺ T-Cell Signature for Risk Stratification of Post-Weaning Mortality in Venoarterial Extracorporeal Membrane Oxygenation Patients

Zengtao Wang,1,* Xing Hao,2,* Junyan Han,1,* Chenglong Li,2 Liangshan Wang,2 Jing Chen,2 Jie Chen,2 Yu Cao,1 Yu Jiang,1 Haoyu Ji,1 Jiarui Li,1 Ju Zhang,1 Hong Wang,2 Mingxi Hua,1 Hui Zeng,1 Xiaotong Hou,2 Chen Chen1 1Biomedical Innovation Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, People’s Republic of China; 2Center for Cardiac Intensive Care, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chen Chen, Biomedical Innovation Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, People’s Republic of China, Email [email protected] Xiaotong Hou, Department of Cardiopulmonary Bypass, Center for Cardiac Intensive Care, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, People’s Republic of China, Email [email protected]: Mortality after successful weaning from venoarterial extracorporeal membrane oxygenation (VA-ECMO) remains common, yet few immune biomarkers enable post-weaning risk stratification. We examined whether circulating CD4⁺ T-cell subsets defined by programmed cell death protein 1 (PD-1) and T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) were associated with off-ECMO mortality in adults supported with VA-ECMO.Methods: We conducted flow cytometric profiling of circulating T cells in 125 adult VA-ECMO patients, classified as survivors (n = 70), on-ECMO mortality (n = 33), and off-ECMO mortality after successful weaning (n = 22). We first quantified CD3⁺, CD4⁺, and CD8⁺ T-cell counts using BD Trucount tubes, and assessed conventional CD4⁺ and CD8⁺ differentiation subsets by flow cytometry. We then quantified PD-1/TIGIT-defined CD4⁺ T cell subsets and assessed their ability to discriminate off-ECMO mortality among successfully weaned patients using receiver operating characteristic (ROC) analyses with bootstrap resampling. A PD-1/TIGIT-based risk classification was constructed using ROC-derived cut-offs.Results: Although CD3⁺/CD4⁺/CD8⁺ T-cell counts and conventional CD4⁺ differentiation subsets did not differ across outcome groups, the off-ECMO mortality group showed a higher frequency of CD4⁺PD-1−TIGIT⁺ T cells [8.36% (5.65– 11.78) vs 5.37% (3.90– 7.15), p = 0.005] and a lower frequency of CD4⁺PD-1⁺TIGIT− T cells [10.90% (7.92– 14.25) vs 14.95% (10.78– 21.85), p = 0.017] compared with survivors. On day 1 of ECMO support, these subsets discriminated off-ECMO mortality with areas under the curve (AUCs) of 0.729 and 0.702, respectively. Based on ROC-derived cut-offs, off-ECMO mortality rates were 10.53%, 16.22%, and 70.59% in the low-, intermediate-, and high-risk groups.Conclusion: A circulating CD4⁺ T cell signature defined by PD-1 and TIGIT expression associates with off-ECMO mortality and may aid risk stratification after VA-ECMO weaning.Keywords: VA-ECMO, immune dysregulation, PD-1, TIGIT, CD4⁺ T cells, risk stratification