“…There was Sherwood Lawrence's transfer factor, a low molecular weight (<10 kDa) leucocyte extract that attracted a great deal of interest because it could apparently induce antigen‐specific T‐cell immunity. It was used to treat patients with T‐cell immunodeficiencies like autoimmune polyendocrinopathy candidiasis ectodermal dystrophy 12 and multiple sclerosis 13 where it appeared to be beneficial despite, in retrospect, lacking any known cytokines. Like the original suppressor T cells, it vanished from the clinical arena in the early 1980s, never to return (in contrast to the re‐emergence of suppressor T cells in the guise of Tregs).…”