More recently this approach has suggested that AITL may be derived from follicular helper T cells that are normally present in germinal centres and that a subset of CD30-negative PTCL, NOS may derive from or be related to AITL [11], [12]; while the remaining PTCL, NOS are most closely related to activated peripheral T lymphocytes [13]. This evidence concerns the gene TNFRSF8 and mature T-cell and NK-cell non-Hodgkin lymphoma.