Pan-Immune Inflammation Value and Clinical Outcomes in Subacute Sclerosing Panencephalitis: A Retrospective Study.

Subacute sclerosing panencephalitis (SSPE) is a rare, progressive, and fatal neurological disorder caused by persistent measles virus infection. Reliable prognostic biomarkers remain limited. Systemic inflammation has been implicated in the pathogenesis of neuroinfectious diseases, and hematology-derived indices are increasingly recognized as accessible markers of inflammatory burden. This retrospective case-control study was conducted at İnönü University Faculty of Medicine, Malatya, Türkiye, between 2010 and 2025, including 40 pediatric patients with SSPE and 40 age- and sex-matched healthy controls. Demographic and laboratory data were retrieved from institutional records, and disease severity was classified according to Jabbour stages. Compared with controls, patients with SSPE had significantly higher pan-immune inflammation value (PIV: 710.5 [320-1050] vs. 280.0 [150-460], p < 0.001), systemic immune-inflammation index (SII: 640.0 [310-1240] vs. 410.0 [210-720], p = 0.02), and neutrophil-to-lymphocyte ratio (NLR: 2.1 [1.2-3.8] vs. 1.6 [1.0-2.5], p = 0.03), along with lower lymphocyte counts (p = 0.04). Elevated PIVs were strongly associated with advanced Jabbour stages, impaired ambulation, and a higher case-fatality ratio (35%). Multivariate regression identified PIV as an independent predictor of death (OR: 3.25, 95% CI: 1.45-7.28, p = 0.004), and receiver operating characteristic analysis demonstrated superior discriminative accuracy of PIV (AUC = 0.87) compared with other indices. These findings suggest that PIV, a simple and inexpensive biomarker derived from routine blood tests, may provide useful prognostic information in SSPE and aid early risk stratification. Further multicenter, prospective studies are warranted to validate its clinical utility.