CD4 T Helper Cell Subsets and Related Human Immunological Disorders

Area of Science:

• Immunology
• Cell Biology

Background:

• CD4 T helper cells orchestrate adaptive immunity, with five major subsets identified: Th1, Th2, Th17, Tfh, and Treg.
• Each subset is characterized by specific cytokines and transcription factors, mediating distinct immune responses against various pathogens.
• Innate lymphoid cells (ILCs) functionally parallel Th1, Th2, and Th17 cells, forming ILC1, ILC2, and ILC3 subsets.

Purpose of the Study:

• To review the differentiation and functions of CD4 T helper cell subsets.
• To discuss the functional parallels between CD4 T helper cells and innate lymphoid cells (ILCs).
• To examine human diseases linked to the dysregulation of these lymphocyte subsets, particularly those caused by monogenic mutations.

Main Methods:

• Literature review of immunological research on CD4 T helper cell subsets and ILCs.
• Analysis of differentiation pathways, key transcription factors, and cytokine profiles.
• Correlation of lymphocyte subset dysregulation with specific human diseases and genetic mutations.

Main Results:

• Th1 cells (IFN-γ, T-bet) combat intracellular pathogens.
• Th2 cells (IL-4/5/13, GATA3) target extracellular parasites.
• Th17 cells (IL-17/22, RORγt) defend against bacteria and fungi; Tfh cells (IL-21, Bcl6) aid B cell antibody production; Treg cells (Foxp3) maintain immune homeostasis and prevent pathology.
• ILCs (ILC1, ILC2, ILC3) mimic effector T helper cell functions.

Conclusions:

• Understanding CD4 T helper cell subsets and ILCs is crucial for comprehending immune responses.
• Dysregulation of these cells, especially due to monogenic mutations, contributes to various human diseases.
• Further research into these cellular pathways can inform therapeutic strategies for immune-related disorders.