TABLE 3.

Clinical and epidemiologic differences in CAEBV by geographic region (12)

Feature	Asia (Japan, East Asia, some Latin America)	United States/Western countries
Predominant infected cell type	Predominantly T-cells or NK cells; B-cell disease is uncommon	Mixed; B-cell disease common, but T- or NK-cell CAEBV also reported
Geographic distribution	Markedly enriched in East Asia (Japan, China, Korea) and also reported in Latin America; patterns suggest possible genetic predisposition	Rare overall; smaller cohorts and registries with mixed B- and T/NK-cell phenotypes
Age at onset	Often pediatric or young adult; large Japanese series show median onset in adolescence/young adulthood, many <20 years	Broader age range with substantial adult onset; B-cell-predominant cases often present later
Presenting symptoms	Persistent/recurrent fever, lymphadenopathy, splenomegaly, hepatitis, cytopenias; often progresses to HLH or EBV-positive lymphoma	Fever, lymphadenopathy, splenomegaly, hepatitis, cytopenias; may progress to HLH or EBV-positive lymphoma
Curative therapy	Allogeneic hematopoietic stem cell transplantation is the only consistently curative approach	Same as Asia