I find this so hard to understand! I thought the immune system either wins or loses categorically. It's clearly not like that though, more like an ongoing battle maybe?
I would much prefer it to be gone, just like a virus - with only the memory of what it looks like etched into the killer T cells memories
Also, I think we need to be careful saying zero risk - whilst I would love to believe this, I think the risk is still there - just predicted to be low based on the research so far
The immune system (and our other systems as well) does not function in a win/lose kind of way. It functions in a 'it's good enough' kind of way. It's helpful to think of immune response as a form of crowd control; a couple of bad actors hanging out on a street corner - no big deal, local police can handle it, but hundreds of bad actors? - need to bring out the Guard. Our immune system responds in a similar way - but via protein signals expressed by the cancer cells (http://www.merckmanu.../tumor-antigens). It takes a critical amount for the immune system to ramp up. And in some cases, for whatever reason, it ramps up too late or with not enough. We're all unique on on how our immune system responds. In some cases eradication may occur (impossible to know for sure) - or in others, a low level residual is tolerated.
In the same way that a germ triggers an immune response (as do cancer cells), other triggers are necessary to end the response and to shrink the population of defending white blood cells. This is why our white blood cell count can dramatically change up and down depending on the state of infection. What makes cancer cells hideous is that they have a secret weapon that foreign germs do not. Cancer cells are 'self' and have "inside knowledge" - they produce triggers to tell our immune system to stand down while they proliferate. So the cells multiply and multiply and our immune system ignores it. That's the crux of the problem. But it does take a lot of cancer cells producing the triggers to tell the immune system to stand down. What this threshold is and how to sensitize the immune system to a lower threshold is the subject of much research:
Cancer cells are created by our bodies all of the time. The reason we do not get cancer disease is because at low levels, these cells are not able to stand down the immune system and either will get eradicated (to the extent that eradication can actually ever occur) or go into quiescence. But for whatever reason - over time, perhaps when the immune system is weakened, the triggering threshold for cancer proliferation is crossed - and the cancer grows and is not able to be stopped by the body alone. And keep in mind, cancer cells themselves, including CML, have internal triggers to cause the cells to die on their own (apoptosis) when DNA errors occur. So a lot has to go wrong for cancer to establish. The establishment of CML disease is a perfect storm of a lot going wrong.
In my case, there is no doubt I have CML - I have a positive PCR result for the bcr-abl protein. The only way this protein is made is by a Leukemic cell. It takes a million of these cells circulating in our entire body before there is enough material in a blood sample for the PCR test to detect the presence of the bcr-abl protein. But to put in perspective, our bodies are circulating over 30 trillion blood cells (5 million alone are in a drop of blood). One million out of 30 trillion is a very low number expressed as a percent. This why PCR is so useful - it detects at the molecular level the bcr-abl protein long before we actually have any disease symptoms.
In my CML case, I have no apparent expansion of the disease currently - although I am testing one month at a time. My PCR is hovering up and down below MMR - without the use of a TKI for the last nine months. Why? Two explanations are reasonable. One - my immune system is checking the expansion of the disease. It's keeping it at a very low level. Or two - The disease itself is quiescent, more or less, and not triggered to proliferate for whatever reason at this time. It may never proliferate again, or I'll have a big jump in PCR and will have to resume therapy. I'm just fine with one and two working together in order to avoid taking Sprycel.
I do wonder, how many "normal" people, if tested for bcr-abl, would test positive? The only people who get tested are the ones who show up at their doctor complaining of painful spleens, high wbc counts, pain, fever and other symptoms. It's my personal belief that there are probably a lot of people in the general population who would have a positive detection for bcr-abl who will never CML disease. Their immune system is doing its job.
Edited by scuba, 04 October 2015 - 09:37 AM.
Diagnosed 11 May 2011 (100% FiSH, 155% PCR)
with b2a2 BCR-ABL fusion transcript coding for the 210kDa BCR-ABL protein
Sprycel: 20 mg per day - taken at lights out with Quercetin and/or Magnesium Taurate
6-8 grams Curcumin C3 complex.
2015 PCR: < 0.01% (M.D. Anderson scale)
2016 PCR: < 0.01% (M.D. Anderson scale)
March 2017 PCR: 0.01% (M.D. Anderson scale)
June 2017 PCR: "undetected"
September 2017 PCR: "undetected"