Kaposi Sarcoma of Childhood: Inborn or Acquired Immunodeficiency to Oncogenic HHV-8

Kaposi sarcoma (KS) is an endothelial malignancy caused by human herpes virus‐8 (HHV‐8) infection. The epidemic and iatrogenic forms of childhood KS result from a profound and acquired T cell deficiency. Recent studies have shown that classic KS of childhood can result from rare single‐gene inborn errors of immunity, with mutations in WAS, IFNGR1, STIM1, and TNFRSF4. The pathogenesis of the endemic form of childhood KS has remained elusive. We review childhood KS pathogenesis and its relationship to inherited and acquired immunodeficiency to oncogenic HHV‐8.