Rapid tear IL-6 detection using the i-ImmunDx™ platform for early diagnosis of ocular GVHD

This study aimed to develop a predictive nomogram model and to validate the value of tear interleukin-6 (IL-6) detection using the i-ImmunDx™ platform combined with ocular surface signs for the early diagnosis of ocular graft-versus-host disease (oGVHD). A total of 79 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the Fourth Affiliated Hospital of Soochow University from November 2021 to July 2024 were enrolled. They were randomly divided into a training set (49 cases) and a validation set (30 cases). Tear inflammatory factors in the training set were detected using flow cytometric bead array (CBA), while the validation set was analyzed with the i-ImmunDx™ system. Ocular surface signs, including lid margin hyperemia, lid margin irregularity, meibomian gland obstruction, meibum quality and conjunctival lesion were recorded for all patients. Stepwise logistic regression identified ln(IL-6), lid margin hyperemia, lid margin irregularity, and meibomian gland obstruction as significant predictors associated with oGVHD. A nomogram model was constructed based on these factors. The model’s performance was evaluated using receiver operating characteristic (ROC) curves, Hosmer-Lemeshow tests, and decision curve analysis (DCA). The area under the curve (AUC) values for the training and validation sets were 0.93 (95% CI: 0.85-1.00) and 0.76 (95% CI: 0.57–0.95), respectively. Hosmer-Lemeshow tests indicated good calibration (training set: p = 0.362, validation set: p = 0.335), and DCA demonstrated that the model provided significantly greater clinical benefits compared to other approaches. The i-ImmunDx™ platform enables rapid and accurate detection of tear IL-6. The nomogram showed acceptable discriminatory performance in the validation cohort and may serve as a preliminary risk-stratification tool. Additionally, the i-ImmunDx™ system exhibits advantages in sample requirements, detection efficiency, and operational simplicity, making it well-suited for primary care settings.