Pathophysiology of Chronic Fatigue Syndrome - Immunological Dysfunction

Immunological Dysfunction

Immunological factors including a chronic activation or suppression of the immune system may contribute to symptoms of CFS, but they may not represent the entire picture and some CFS experts doubt they are responsible. A 2003 review concluded that "no consistent pattern of immunological abnormalities is identified" in CFS. A 2009 review into the immunological aspects of CFS reported that patients do seem to have a specific immune dysfunction profile involving an enhanced baseline activation of lymphoid subsets but a suppression of certain immune responses, particularly Th1-driven ones such as the anti-viral and anti-tumour responses. Reported findings from various studies include an alteration in cytokine profile (high level of pro-inflammatory cytokines and dysregulation of anti-inflammatory cytokines), decreased function of natural killer (NK) cells, the presence of autoantibodies, reduced responses of T cells and abnormal activation of T lymphocyte subsets. The authors note that the immune alteration pattern of CFS "has a striking resemblance to the one caused by developmental immune toxicology", perhaps due to a combination of factors such as xenobiotics, infections and stress.

Allergies or food intolerance have been reported in CFS sufferers. Gene expression changes have been reported in the white blood cells of CFS patients. This is consistent with the theory of abnormal types of antiviral protein RNase L and are postulated to affect sleep-wake cycles and exercise capacity. High levels of Th2-type cytokines and the cells that make them are also found in CFS. Therapeutic alterations of cytokine expression patterns are being investigated.

In contrast, immunodeficiency disorders characterized by abnormal T-cell subset ratios, levels of immunoglobulins, and hypoallergic responses on the French Multitest have been reported in CFS.