J Korean Med Assoc.  2009 Jul;52(7):638-644. 10.5124/jkma.2009.52.7.638.

Introduction to Autoimmune Disease

• Kim J
• Choe J

• KMID: 2188024
• DOI: http://doi.org/10.5124/jkma.2009.52.7.638

Abstract

The immune system maintains the integrity of our bodies by warding off intruding microorganisms, but by sustaining tolerance to our own tissues. The immunologic tolerance is established by several layers of safeguards, including physical elimination of self-reactive lymphocytes during their development in the central lymphoid organs, anergy induction in autoreactive lymphocytes before their emigration to the periphery, or production regulatory T lymphocytes that suppress the activation, proliferation, and differentiation of various effector cells. The major regulatory T lymphocytes display their phenotype as CD4(+)CD25(+)Foxp3(+) and constitute about 10% of the peripheral T lymphocytes. Even with these safeguards, the immunologic tolerance sometimes fails and generates autoimmune diseases. Scientists studying the pathogenesis of autoimmune diseases pay particular attention to a CD4(+) T lymphocytes subset, Th17 lymphocytes, distinct from Th1 and Th2. Th17 produces diverse proinflammatory cytokines including IL-17 and TNF-alpha. Th17 and these cytokines are causatively associated with many episodes of autoimmune diseases. Accumulated data reveal the critical role of Th17 cells in the pathology of autoimmunity and portray them as an important target in the treatment of various autoimmune diseases. In this article, we will describe the main characteristics of regulatory T cells and Th17 cells and their cellular and molecular mechanisms of protective or destructive functions, respectively.

Keyword

Autoimmune disease; Immunologic tolerance; Regulatory T cell; Th17

MeSH Terms

Autoimmune Diseases
Autoimmunity
Cytokines
Emigration and Immigration
Immune System
Interleukin-17
Lymphocytes
Phenotype
T-Lymphocytes
T-Lymphocytes, Regulatory
Th17 Cells
Tumor Necrosis Factor-alpha
Cytokines
Interleukin-17
Tumor Necrosis Factor-alpha

Figure

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  Figure 1 Differentiation pathway of murine Treg and Th17 cells.

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  Figure 2 The critical role of Treg and Th17 in immunologic self-tolerance and autoimmune diseases.

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