CD4+ T helper (TH) cells regulate appropriate cellular and humoral immune responses to a wide range of pathogens and are central to the success of vaccines. However, their dysregulation can cause allergies and autoimmune diseases. The CD4+ T cell population is characterized not only by a range of distinct cell subsets, such as TH1, TH2 and TH17 cells, regulatory T cells and T follicular helper cells — each with specific functions and gene expression programmes — but also by plasticity between the different TH cell subsets. In this Review, we discuss recent advances and emerging ideas about how microRNAs — small endogenously expressed oligonucleotides that modulate gene expression — are involved in the regulatory networks that determine TH cell fate decisions and that regulate their effector functions.
At a glance
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