Scarce data exists on pathomechanisms of TAMA beyond the common background of cellular autoimmunity in thymoma e.g. errors in negative T-cells selection, decreased expression of autoimmune regulator – AIRE gene, overproduction of CD4+ and CD8+ single-positive and immature CD4+CD8+ double-positive T-cells, decreased Treg number and decreased major histocompatibility complex (MHC) class II expression (25, 32, 39, 40). Here, CD4 is linked to thymoma.