“…There are some pathological conditions in which antigen persistence is associated with the expansion of a CD4 + T‐cell subset bearing the CD57 marker, i.e. human immunodeficiency virus (HIV) infection, 9 renal or bone marrow allograft transplant, 10,11 chronic lymphocytic leukaemia, 12,13 colorectal cancer, 14,15 rheumatoid arthritis 16,17 and malarial infection 18 . CD57 is the sulfated polysaccharide SO 4 ‐3GlcAβ1,3Galβ1,4‐GlcNAc (also known as HNK‐1 or Leu‐7), which is present on several cell‐surface glycoproteins and glycolipids 19,20 and on unconventional T cells 10,18 .…”