Th17 cells in autoimmune disease: changing the verdict

Area of Science:

• Immunology
• Autoimmunity
• Neuroinflammation

Background:

• T helper 17 (Th17) cells and their cytokine IL-17 were considered the primary drivers of autoimmune diseases, supplanting T helper 1 (Th1) cells.
• Previous evidence establishing Th1 cells as the sole encephalitogenic T-cell effector type has been challenged.
• Accumulating data questions the central role of Th17 cells in the pathogenesis of autoimmunity.

Purpose of the Study:

• To re-evaluate the roles of Th1 and Th17 cells in autoimmune neuroinflammation.
• To investigate the parallel functions and distinct effector mechanisms of Th1 and Th17 cells in disease.

Main Methods:

• Analysis of recent high-impact publications.
• Examination of two mouse models for autoimmune neuroinflammation.

Main Results:

• Four recent studies demonstrate that both Th1 and Th17 cells possess encephalitogenic properties.
• The dominance of either Th1 or Th17 cells can dictate disease severity in autoimmune conditions.
• In experimental autoimmune neuroinflammation models, Th1 and Th17 cells were observed to function in parallel.

Conclusions:

• Both Th1 and Th17 cells are critical effector populations in autoimmune diseases.
• These distinct T-cell subsets operate concurrently, employing different mechanisms to drive neuroinflammation.
• Understanding the parallel roles of Th1 and Th17 cells is crucial for developing targeted autoimmune therapies.