T helper cell

T helper (Th) cells play an important role in the adaptive immune system. T helper cells are often distinguished from cytotoxic T cells by the surface antigens CD4 and CD8. T helper cells carry the CD4 surface antigen while cytotoxic T cells carry the CD8 surface antigen. T helper cells and cytotoxic T cells are the best known types of T cells.

Th1
Th1 cells are a subset of T helper cells that are involved in cell-mediated immunity against viruses and intracellular bacteria. They are triggered by IL-12, IL-2 and their effector cytokine is IFN-γ. The main effector cells of Th1 immunity are macrophages as well as CD8 T cells, IgG B cells, and IFN-γ CD4 T cells.

Autoimmune diseases characterized by a Th1 immune profile include rheumatoid arthritis, multiple sclerosis, type 1 diabetes, Sjögren's syndrome and Crohn's disease.

Th2
Th2 cells are a subset of T helper cells that are involved in humoral immunity against extracellular parasites, bacteria, toxins and allergens. They are triggered by IL-4 and their effector cytokines are IL-4, IL-5, IL-9, IL-10 and IL-13. The main effector cells are eosinophils, basophils, and mast cells as well as B cells, and IL-4/IL-5 CD4 T cells.

Autoimmune diseases characterized by a Th2 immune profile include Lupus, scleroderma, inflammatory bowel disease, and Asthma. Chronic fatigue syndrome may be characterized by a Th2 cytokine profile.

Th17
The T-helper cell 17 (Th17) lineage is a recently discovered subset of effector memory T cells.

Modulating the Th1/Th2 balance
There are many compounds that have been suggested to suppress a Th2-mediated immune response, inducing a shift toward a Th1-type response. These include ginger, reishi , licorice and astragalus. These have not been tested for efficacy in ME or CFS patients.

Histamine and mold increase a Th2 response.