Using a major histocompatibility complex (MHC) tetrameric assay to assess the presence of T-cells with receptors matching with the ALK peptide p280-89 in the peripheral blood mononuclear cells (PBMC) of tested subjects, high levels of anti-ALK CD8+ repertoire were detected in both ALK-positive ALCL patients and healthy subjects. The gene discussed is CD8A; the disease is anaplastic large cell lymphoma.