Editing T helper cell (section)

{{Short description|Type of immune cell}}
{{redirect|Th2|the professional wrestling tag team|The Hybrid 2}}

[[File:Activation of T and B cells.png|thumb|right|400px|Activation of macrophage or B cell by T helper cell]]
The '''T helper cells''' ('''T<sub>h</sub> cells'''), also known as '''CD4<sup>+</sup> cells''' or '''CD4-positive cells''', are a type of [[T cell]] that play an important role in the [[adaptive immune system]]. They aid the activity of other immune cells by releasing [[cytokines]]. They are considered essential in [[B cell]] [[Immunoglobulin class switching|antibody class switching]], breaking [[Cross-presentation|cross-tolerance]] in dendritic cells, in the activation and growth of [[cytotoxic T cell]]s, and in maximizing [[bactericidal]] activity of [[phagocytes]] such as [[macrophages]] and [[neutrophil]]s. CD4<sup>+</sup> cells are mature T<sub>h</sub> cells that express the surface protein CD4. Genetic variation in regulatory elements expressed by CD4<sup>+</sup> cells determines susceptibility to a broad class of [[autoimmune disease]]s.<ref>{{cite journal | vauthors = Burren OS, Rubio García A, Javierre BM, Rainbow DB, Cairns J, Cooper NJ, Lambourne JJ, Schofield E, Castro Dopico X, Ferreira RC, Coulson R, Burden F, Rowlston SP, Downes K, Wingett SW, Frontini M, Ouwehand WH, Fraser P, Spivakov M, Todd JA, Wicker LS, Cutler AJ, Wallace C | display-authors = 6 | title = Chromosome contacts in activated T cells identify autoimmune disease candidate genes | journal = Genome Biology | volume = 18 | issue = 1 | pages = 165 | date = September 2017 | pmid = 28870212 | pmc = 5584004 | doi = 10.1186/s13059-017-1285-0 | doi-access = free }}</ref>