Can I ask a question? How do we know those IGG titers ARE significant? Have they compared our viral load with that of healthy people or some control group? I also test high on EBV and HHV6 IGG (including early antigen on the EBV). CFS specialist says these are significant, mainstream infectious disease Doctor says no - these indicate past infection only. She said the way to really check is PCR, see if it's in the DNA. So she tested that way, but ran the wrong one - I forget now if it was quantitative or qualitative, but one can pick up past infection and I told her that and asked to have the other one run and that came back completely negative for EBV. Anyway, I'm not saying viruses aren't the problem, but how do we know? Have they ever compared our IGG's to other groups to see if we have higher loads? Have there been any studies like this?
We don't know for certain what viral load is significant for us. The only thing certain in this illness is that there's no certainties.
The rule-of-thumb thinking is that (relatively old) studies have shown that (what they thought were) healthy people can have relatively high IgG titres to EBV, CMV, HHV-6, so high titres don't mean anything other than your immune system was exposed to the virus once and is now producing antibodies. Ho hum.
The problem is, the actual information is quite limited, as far as I can tell. They didn't sort by age, length of time since exposure to the virus, undiagnosed symptoms, and loads of other possible confounding factors.
The questions arise when the patient is clearly NOT healthy, or has immune abnormalities. Some more progressive doctors -- especially those who've actually had to rethink their view of virus infection since HIV hit our awareness -- are thinking that the all-or-nothing rule of thumb is grossly overused.
Here's some of the thinking I've heard about. There's probably a lot more. It may not all be perfectly accurate, but you'll get the idea.
1) While high IgG titres may be normal in healthy people within a few years of infection, a high titre in a person whose initial infection was probably decades earlier (the case for most adults who had their primary infections of HHV-6 and CMV before age 2, and EBV before age 21) is suspicious. Antibodies do tend to drop off slowly over a long time. Why else would people need the shingles vaccine (aka chicken pox booster)?
2) The primary weak assumption in the high titres = no big deal is that everyone's immune system can keep latent viruses in check -- except for people born with severe genetic immune deficiencies. That idea has changed since we've learned more about milder immune deficiencies and acquired immune deficiencies. Unfortunately many, many docs are still using old information.
3) High titres in
healthy people are no big deal. High titres in people with symptoms of the illness, on the other hand, can signify an illness state. Too many doctors forget that caveat.
Some (all?) labs that test for herpesviruses have a qualifier in the analysis that says the test should be used
along with clinical signs to evaluate the presence of active infection. Many docs ignore that part, especially if they don't believe ME/CFS patients are really ill.
4) Most doctors assume ME/CFS patients have normal immune systems and can therefore keep herpesviruses in latency just like everybody else. I've had more than one doctor admit that if I had HIV, s/he'd be concerned about my high titres. "But HIV patients have immune dysfunction. You don't. So it's not an issue." Note that neither doc had any immune testing done to justify their assumption that I didn't have immune dysfunction. They just assumed and acted on their incorrect assumption.
5) Testing for EBV, CMV, HHV-6 is far from perfect. HHV-6 testing, in particular, is questionable. Not bad, but certainly not 100%. See
this information about testing at the HHV-6 Foundation. It will give you some idea of what the issues are.
6) Antibody titres are an indirect measure. They don't measure the virus itself, they measure how many antibodies to the virus your body is producing. What if your body doesn't produce antibodies properly as in immunoglobulin deficiencies? Then your antibody numbers would not correlate (as well as assumed) with your level of infection. There are a number of other issues with indirect measures, but I've now used up all my current mental energy, so I'll leave it at that.
Bottom line -- antibody titres are useful, but not 100% conclusive measures of infection. Even PCR on blood has it's limitations, such as in cases where the infection is mostly tissue-based so the viral levels in the blood are low even when tissue infection is high. (Or something like that.... my brain is giving out.
)
Folks, we have no guarantees of anything in this illness. It's true in medicine in general, and even more so in ME/CFS. We have to do the best we can with the limited data we can get. That includes not taking anything at face value.
Ow. My head needs a rest.