Dynamics of virological suppression and systemic immune-inflammatory response following antiretroviral therapy in pediatric HIV infection.

Background: Persistent systemic inflammation remains a hallmark of treated HIV infection and is not reliably resolved by virological suppression alone. The Systemic Immune-Inflammation Index (SII), a composite hematologic index [(neutrophil × platelet)/lymphocyte count], has emerged as a candidate inflammatory biomarker. Longitudinal SII data following antiretroviral therapy (ART) initiation in pediatric HIV are lacking. Methods: This single-center retrospective paired longitudinal study included 30 pediatric patients with HIV with laboratory data at baseline and 12 months post-ART. The primary outcome was change in SII; secondary outcomes included CD4%, HIV RNA, and double-negative T-cell percentage (DNT%). Non-improvers were characterized by age, sex, ART regimen, nutritional status, and co-infection status. Paired comparisons used the Wilcoxon signed-rank test; Spearman correlation was the primary inferential method, with Pearson as a sensitivity analysis. Results: Median SII declined numerically (342,637 to 250,527) but did not reach significance ( Conclusion: In this pediatric HIV cohort, SII failed to improve in nearly half of patients despite successful ART, dissociating from both CD4 reconstitution and HIV RNA suppression. These findings suggest SII reflects a residual inflammatory state driven by mechanisms beyond viral replication, including ART class-specific, sex-related, and developmental factors. Routine SII monitoring may identify patients at ongoing inflammatory risk despite virological success; larger prospective studies are needed.