One physician I know gives all his patients the methylation treatment, and then watches the response. If they experience some symptoms that appear to be caused by detox, but they are able to tolerate them, he continues with this treatment. If they have intolerable symptoms that appear to be related to mobilization of toxins, then he stops the methylation treatment and works on improving the status of the gut. When that is working better, he moves on to supporting the liver. His thinking is that the toxins that were being mobilized were being reabsorbed by the gut and sent back to the liver. In order to properly process and excrete the toxins, the gut and liver must both be functioning well enough to handle them.
My guess is that when there is an inflammation response to methylation cycle treatment, there is an infection. If the inflammation continues without resolution, then my guess is that the immune system has been reactivated, but is not capable of defeating an existing infection. In such cases, I think that treating to support the immune system would be one approach. Another would be to test to determine what pathogen is causing the infection, and then treating it with an antibiotic, antiviral or antifungal, depending on the pathogen.
I think it's important to note that a healthy person would not have any reaction to the supplements used in the methylation protocols, because their methylation cycle, detox system and immune system would already be functioning normally. So the fact that there is a response, even though it may seem to be deleterious, means that the methylation cycle was partially blocked and that these supplements were needed. However, the way one should proceed from that point on probably depends on the type of response that the individual person has.
So far, I'm pretty sure that if the following are present, they will need specific treatment, in addition to treating the methylation cycle partial block: biotoxin (including mold) illness, Lyme disease and its coinfections, well-entrenched viral infections, and high body burdens of toxic heavy metals, such as mercury. There may be others of which I'm not aware, but there is some experience with these, at least, which people have reported
I believe that the partial methylation cycle block is the pivotal abnormality in the pathogenesis and pathophysiology. With respect to the root cause or causes (etiology) of ME/CFS, I have suggested that this disorder arises from a combination of a genetic predisposition and some combination of a variety of stressors, which can be physical. chemical, biological, or psychological/emotional. I've suggested that this combination leads to glutathione depletion, which leaves B12 unprotected, which causes a decreased production of methylacobalamin, which inhibits methionine synthase, which forms a vicious circle with glutathione depletion, making ME/CFS a chronic condition. The retroviruses would fit within the biological stressors in my hypothesis, and certainly could be a root cause. If effective treatment of the retroviruses ends up bringing about recovery from ME/CFS, that will be very convincing as to its role as an etiologic agent. I hope that turns out to be the case for at least some of the PWMEs/PWCs. It may not be true for all of them, though, because this population seems to be very heterogeneous.
The reason I have included the variety of stressors as etiologic agents is that I have studied the published "risk factor" studies, and have also queried quite a few PWMEs/PWCs as to the events that preceded their onset, and I've found a variety of precursors. The common factor seems to be that they are all things that would be dealt with by the body's nonspecific stress response systems, and these in turn are known to place demands on glutathione.
In addition to this, there are now many PWMEs/PWCs who have taken the Health Diagnostics methylation pathways panel, and nearly all of them show evidence of a partial methylation cycle block or glutathione depletion, and usually both.
And when treatment was given in our clinical study that is directed toward lifting the partial methylation cycle block, we observed by testing that this does in fact occur, and that glutathione also comes up automatically. This was accompanied by improvement in symptoms in at least two-thirds of those who were treated.
Putting all of this together, I think the GD-MCB hypothesis is consistent with the observations and with known biochemistry and physiology. That doesn't mean that I believe that it is scientifically proven, which is a very high standard to meet, and requires considerable investment in time, money and effort, but that it is a valid working hypothesis. I'm hoping to interest researchers and fundors in this model so that it can be more thoroughly tested.
The methylation cycle is at the beginning of the sulfur metabolism. It is fed by methionine, which comes in as part of protein in the diet. Homocysteine is produced from methionine (via SAMe and SAH) in the methylation cycle, and then methionine synthase "decides" how much should be converted back to methionine, to stay in the methylation cycle. In the liver and kidneys, the BHMT reaction also converts some homocysteine back to methionine. The rest of the homocysteine enters the transsulfuration pathway, which is downstream.
The way that methionine synthase does its "deciding" is that the cobalt ion in the cobalamin that is its cofactor gets oxidized at a rate that depends on the state of oxidative stress in the cells. The more oxidizing this state is, the more often the cobalt ion gets oxidized, and that temporarily shuts down the methionine synthase reaction and diverts the homocysteine flow into the transsulfuration pathway, which helps to make more glutathione, which counters the oxidative stress. Unfortunately, in ME/CFS this delicate mechanism gets overwhelmed, and the oxidative stress becomes more severe, so that glutathione doesn't recover and get control of it. The result is that methionine synthase becomes partially blocked, and the sulfur metabolites drain down the transsulfuration pathway, into sulfoxidation, and get excreted too much as taurine and sulfate, which depletes methionine. The whole sulfur metabolism becomes dysfunctional, and that takes down the cell-mediated immune response as well as the detoxication system. As well, everything that depends on methylation reactions is affected, including gene expression, synthesis of several needed substances, and the neurotransmitter metabolism. Also, this drains the folates from the cells via the methyl trap mechanism, and that affects things that depend on folate, such as synthesis of new RNA and DNA. The latter is what cause the red blood cells to be too big and too few in number.
The methylation cycle is so fundamental to so many parts of the body's biochemistry that when it becomes dysfunctional, it causes a host of problems, and this is why people experience so many symptoms, involving so many body systems and organs, in this disorder.