René Hage, Irina Lea Dubach, Carolin Steinack, Zsófia Rosselli, Macé M. Schuurmans
Experimental and Clinical Transplantation - 2025;23(11):734-742
Objectives: The neutrophil-to-lymphocyte ratio is an inexpensive and accessible inflammatory biomarker that reflects the balance between innate and adaptive immunity. This study evaluated whether perioperative or early posttransplant neutrophil-to-lymphocyte ratio predicts baseline lung allograft dysfunction or acute cellular rejection within the first year after lung transplant. Materials and Methods: In this single-center retros- pective cohort study, we analyzed 80 adult bilateral lung transplant recipients (transplanted in 2021-2023). Patients had peripheral blood neutrophil-to- lymphocyte ratio measured pretransplant and at 3, 6, 9, and 12 months posttransplant; bronchoalveolar lavage neutrophil-to-lymphocyte ratio was calculated from differential counts when available. We assessed associations between neutrophil-to-lymphocyte ratio, baseline lung allograft dysfunction, and acute cellular rejection within the first year with the Mann-Whitney U test, chi2 test, or Fisher exact test. We performed receiver operating characteristic analysis with Youden index- based cutoffs and multivariable logistic regression adjusted for baseline dysfunction, diagnosis group, and sex . Results: Peripheral blood neutrophil-to-lymphocyte ratio at 3, 6, 9, and 12 months posttransplant was consistently higher in patients with baseline dysfunction than in those without, but differences were not signific ant. Bronchoalveolar lavage neutrophil-to-lymphocyte ratio showed no group differences and substantial variability. Receiver o perating characteristic analyses showed no discriminatory ability of neutrophil-to-lymphocyte ratio to predict acute rejection (area under the curve ~= 0.5 across all time points), and seemingly high sensitivities and specificities at certain cutoffs were artifacts accompanied by negligible Youden indices. In multi-variable models, neither blood nor bronchiolar lavage neutrophil-to-lymphocyte ratio was independently associated with rejection (all P > .05). Median follow-up was 12 mo nths. Conclusions: Neutrophil-to-lymphocyte ratio did not discriminate baseline lung allograft dysfunction or acute rejection, with regression analyses showing no significance. Neutrophil-to-lymphocyte ratio lacks clinical utility as a standalone marker and, if used at all, should be embedded within multimodal surveillance frameworks.
