Vitreous and Serum Levels of IL-1β and IL-33 in Proliferative Diabetic Retinopathy: Evaluation of Local Versus Systemic Inflammatory Signatures

PDR is characterized by concomitant intraocular and systemic upregulation of IL-1β and IL-33, with serum levels consistently exceeding vitreous concentrations and showing partial correlation between compartments. These findings support an IL-1-IL-33-associated inflammatory signature that spans both retinal and systemic levels and highlight IL-1β and IL-33 as potential biomarkers or candidate mediators in advanced PDR.