Long-Term Immune Alterations After Thymectomy in Early Childhood: A Case Series.

The thymus plays a central role in T-lymphocyte maturation and in maintaining immune defense against infections and autoimmunity. We describe three boys (mean age 7.3 years) who underwent total thymectomy during surgical correction of congenital heart disease, two in infancy and one in the neonatal period. Patient A presented (14 years old) with recurrent cervical lymphadenopathy, generalized Epstein-Barr virus (EBV) infection, and hepatic fibrosis. Patient B (two-year-old) developed splenomegaly and had a history of frequent lower respiratory tract infections and pseudohypoaldosteronism type II. Patient C (seven-year-old) presented with generalized lymphadenopathy, hepatosplenomegaly, neutropenia, and thrombocytopenia; his medical history included skeletal anomalies and immune cytopenia with response to intravenous immunoglobulin, but no severe infections. All three patients displayed significantly low naïve CD4 counts, confirming the existence of long-term immune changes following thymectomy. They shared the same immunophenotype, characterized by significantly low naive CD4 cells, which is considered a marker of long-term immune dysregulation following thymectomy. However, their clinical presentation varied, encompassing a spectrum of manifestations ranging from recurrent viral infections to severe immune cytopenias. The immunophenotypic similarities to 22q11.2 deletion syndrome underscore the need to include surgical thymectomy in the differential diagnosis of T-cell dysregulation. Notably, the most severe immune abnormalities were seen after thymectomy during the neonatal period, emphasizing the crucial influence of surgical timing. Long-term immunological monitoring of these children is warranted to anticipate and manage infections or immune-mediated complications.