Lymphocyte subsets predict mortality in acute paraquat poisoning

Paraquat (PQ) is a highly effective herbicide widely used in agricultural production, known for its strong herbicidal power, rapid action, and minimal environmental pollution. However, it is also highly toxic to humans and animals, with acute lung injury (ALI) being the primary cause of death. While the toxic mechanisms of PQ have been studied from various perspectives, its effects on lymphocytes and their subsets remain unclear. This study aimed to explore the relationship between lymphocyte dysfunction and mortality in acute PQ poisoning. A total of 92 patients with PQ poisoning who visited the emergency department of The Affiliated Lihuili Hospital of Ningbo University between January 1, 2016, and September 30, 2021, were included. Basic demographic and laboratory data within 24 h of admission were collected. Peripheral blood lymphocyte subsets were analyzed using flow cytometry. To identify independent risk factors for mortality, patients were followed up for 90 days. COX proportional hazards models and LASSO regression were applied to screen for predictive variables and develop a predictive model. All participants provided informed consent, and the study was approved by the relevant ethics committee. Among the 92 patients, 36 died. Compared with the survival group, the death group showed significantly higher white blood cell and neutrophil counts, lymphocyte counts, and CD4+/CD8+ T cell ratios, while the percentage of natural killer (NK) cells was significantly lower (P < 0.001). COX regression analysis identified these factors as independent risk factors for mortality: lymphocyte count: hazard ratio (HR) = 1.59; 95% confidence interval (CI), 1.02-2.47; P = 0.04 neutrophil count: HR = 1.12; 95% CI, 1.06-1.18; P = 0.04 CD4+/CD8+ T cell ratio: HR = 2.01; 95% CI, 1.03-3.92; P = 0.04 NK cell percentage: HR = 0.88; 95% CI, 0.82-0.95; P = 0.002. These findings suggest that lymphocyte count, neutrophil count, CD4+/CD8+ T cell ratio, and NK cell percentage are all associated with mortality in PQ poisoning cases.