Pediatric Evans Syndrome as a Multisystem Immune Disorder: A 13-Year Longitudinal Experience from a Single Academic Center.

Background: Pediatric-onset Evans syndrome (pES) is a rare autoimmune disorder defined by the coexistence or sequential development of immune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA), frequently accompanied by autoimmune neutropenia (AIN) and characterized by a relapsing, multilineage course. Increasing evidence suggests that pES may represent a broader immune dysregulation phenotype rather than an isolated hematologic disorder. Methods: We conducted a retrospective, single-center study of children diagnosed with pES and followed for up to 13 years at a tertiary referral center. Clinical data regarding hematologic evolution, extra-hematological immunopathological manifestations, treatment requirements, infectious complications, and genetic findings were analyzed descriptively. Results: Six children (4 males) were included, with a median age at first cytopenia of 7 years (range 3-15) and a median follow-up of 8 years (range 1-13). ITP preceded AIHA in 3/6 patients (50%), one patient (16.7%) developed AIHA first, and two (33.3%) showed partial or evolving multilineage disease with DAT positivity prior to overt hemolysis. AIN occurred in 3/6 patients (50%). Extra-hematological immunopathological manifestations occurred in 5/6 patients (83.3%), with two (33.3%) developing more than one. Second-line therapy was required in 3/6 patients (50%). Infectious episodes occurred in 83.3% of patients, predominantly viral or mild bacterial infections, with no life-threatening events. Whole-exome sequencing performed in three patients identified a heterozygous TNFAIP3 variant of uncertain significance in one case; no pathogenic variants were detected. Conclusions: pES demonstrates clinical heterogeneity, frequent multilineage cytopenia, and substantial extra-hematological immune involvement. Multisystem manifestations may be associated with increased treatment burden. Long-term multidisciplinary monitoring and cautious interpretation of genetic findings are essential for individualized pediatric care.