title: Basic science for the clinician 45: CD4+ T-cell subsets of probable clinical consequence.
abstract: I have often said "blessed be the splitters, for they shall inherit the earth." By that I mean that it is only by studying carefully culled populations, approaching, but never quite reaching, homogeneity that we can ever gain real insights into rheumatologic diseases. Differentiating tuberculous from gouty from rheumatoid arthritis was a good start, and when Moll and Wright identified the seronegative spondyloarthropathies, we were on our way to establishing "splitters" as leaders. Predictably, once T cells were identified as different from B cells, the floodgates opened. Subsets galore were described, with more isolated populations in the T-cell family, but we are now finding heterogeneity in B-cell populations, as well, which has been discussed in a previous article in this series. But as for T cells... well, it has not been smooth sailing. I initially trained in a laboratory that was firmly committed to the proposition that there were within the CD8 population not only cytotoxic cells but also "suppressor cells." Problem is, no one could ever isolate the little buggers, and so the idea of a suppressor or regulatory subpopulation of CD8+ T cells went the way of the Edsel. As noted in a previous article in this series, T regulatory cells were finally identified but not within the CD8+ population. And there are other regulatory subsets within both CD4+ and CD8+ T-cells populations and even new effector and memory populations that can be identified by their surface markers and functions. It is high time to review some of them; some of these populations may be involved in the immunopathogenesis of our diseases and undoubtedly will shortly be targets of immunotherapeutics. Although previous articles in this series discussed some of these subsets, I thought expanding on what is known about another recently described subset and putting them all together in one review might be helpful.
authors.affiliation: Pharmaceutical Research Institute, Bristol-Myers Squibb, Princeton, New Jersey 08543-4000, USA. leonard.sigal@bms.com
authors.forename: Leonard H
authors.initials: LH
authors.lastname: Sigal
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000145:classification* / Q000276:immunology; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit; D007694:Killer Cells, Natural / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000145:classification* / Q000276:immunology
chemical_list: D053645:Interleukin-2 Receptor alpha Subunit