The link between circulating follicular helper T cells and autoimmunity

Area of Science:

• Immunology
• Cellular Biology

Background:

• Follicular helper T (T_FH) cells are crucial for B cell help and antibody responses.
• T_FH cells are typically in lymphoid organs but can be found in blood.
• Altered T_FH cell frequency and phenotype are observed in autoimmune diseases.

Purpose of the Study:

• To discuss the increase in circulating T_FH cells in autoimmune settings.
• To explore potential explanations for elevated T_FH cells in autoimmunity.
• To highlight the link between T_FH cell regulation and autoimmune disease pathways.

Main Methods:

• This is a perspective article, involving discussion and synthesis of existing knowledge.
• It considers regulatory pathways of T_FH cell differentiation, including CTLA4, IL-2, and regulatory T cells.
• It examines the role of infection as a trigger for T_FH differentiation and autoimmunity.

Main Results:

• Circulating T_FH cell numbers are often elevated in autoimmune conditions.
• Pathways regulating T_FH cell differentiation (CTLA4, IL-2, Treg) are also key in controlling autoimmunity.
• Infection can influence T_FH differentiation and potentially trigger autoimmune disease.

Conclusions:

• Alterations in autoimmune regulatory pathways correlate with changes in T_FH cell homeostasis.
• Increased circulating T_FH cells may serve as a biomarker for immune dysregulation in autoimmune diseases.
• Understanding T_FH cell biology offers insights into autoimmune disease mechanisms.