Hepatitis E virus in immunocompromised children in Argentina: first report from a high-risk group.

BACKGROUND: Hepatitis E virus (HEV) is an emerging zoonosis that can lead to chronic hepatitis in immunocompromised individuals. While HEV genotype 3 circulates in Argentina, data on pediatric populations, especially those immunosuppressed, are scarce. We hypothesized that immunosuppressed children in a region with known zoonotic HEV circulation would show higher seroprevalence compared to healthy controls. METHODS: This pilot descriptive cross-sectional study was conducted at a pediatric referral center in Rosario, Argentina, from 2018 to 2020. Fifty-eight immunocompromised children (aged 8 months-17 years) were enrolled, alongside 101 age-matched healthy controls. Anti-HEV IgG and IgM antibodies were detected by ELISA; HEV RNA was assessed by RT-qPCR. Statistical analyses included chi-square and logistic regression tests. RESULTS: Anti-HEV IgG was detected in 6.9% (4/58) of immunosuppressed patients, whereas no seropositivity was observed among controls (0/101; p = 0.0075). No cases of active or recent infection (IgM or RNA positive) were found. Anti-HEV IgG prevalence was highest among adolescents (10.0%) and patients with autoimmune diseases (28.6%), though subgroup comparisons lacked statistical significance. One IgG-positive patient had prior intravenous immunoglobulin exposure, suggesting possible passive antibody transfer. CONCLUSIONS: This study provides the first evidence of HEV exposure in immunosuppressed pediatric patients in Argentina, revealing a significantly higher seroprevalence compared to healthy peers. Although no active infections were detected, findings support the need for targeted HEV surveillance in high-risk pediatric groups, particularly in regions with confirmed zoonotic HEV circulation. Future multicenter, longitudinal studies are warranted to evaluate clinical outcomes and guide prevention strategies.