The causes of ME are still unknown. However in many cases ME is associated with non-typical immune responses, allergies and nervous system disorders including cognitive dysfunction, emotional lability, sleep disturbance and fatigue. In my opinion it seems likely that the body's own "defense" mechanisms are involved with producing the effects of the illness after being innappropriately triggered in a manner comparable with allergies or an autoimmune disease. Whether they are triggering themselves under certain conditions or are being triggered by the product of a virus or microbe pathogen is still unclear. The resulting perturbation to the nervous system causes a plethora of neuralgias and these increase patient's sensitivity to stimuli and vulnerability to stress.

There are two pieces of biochemical evidence which corroborate this point of view. The first is the discovery of an unusual enzyme in some ME patients (low weight RNAse-L by Suhadolnik et al) and the second is the discovery of unusual lipids in ME patients (Ciguatera epitope by Hokama et al). Both are considered harmful to their owners and account for many of the symptoms of CFS and both are probably produced by people who are ill as part of their immune responses. There is still a question about what causes these molecules to be made in such large quantities and for so long. It is known that certain viruses can produce fake immune signals (interleukins) and trick the body into producing the wrong kind of immune response and it may be possible that some pathogens can actually cause ME like this. On the other hand it may be that some people have an unfortunate tendency to overreact to immune challenges and so are are predisposed to getting ME from normal immune challenges. It is not inconceivable that both factors may play a part in causing ME and people with a genetic predisposition may be more susceptible to the trick molecules of certain viruses than other people.