Blood oxygen levels and immune systems. Guesses? Opinions?

[Einna]

Okay, I have three main questions. Please bear in mind, all are in a fantasy setting, so some leeway is aloud.

1 - If someone had two immune systems (one like a normal humans, and one in the form of a toxin created by the body) what would happen? Would the first recognize the second as a toxin and attack, or part of the body and leave alone?

2 - Appoximately how much of you bloods oxygen would have to be missing before it would effect you? I suffer from anemia, so I know some stuff about effects and such, but how low would your bloods oxygen need to be before it killed you? Or made you pass out? And if anyone knows how low an average anemics levels are, I'd appreciate knowing that too.

3 - What would happen if you were constantly injecting something into the bloodstream that wasn't being filtered out or absorbed? Would the body stop making as many blood cells, or would the veins eventually rupture from too much liquid in them? The drug injected is a neutralizer to take care of toxin build-up in the blood...can blood also be neutralized?

If you're still with me, please help! And don't give me funky cyber-looks, it's not actually half as barmy as you might think.

Thanks in advance!

[AXJ]

1. If they were born with both, I think they'd obviously not interfere with each other. If the second one was added, I imagine it would depend... after all, we add antibiotics to our own immune systems all the time with no ill effects. But if it were some sort of organism or something, you'd likely need to do something to suppress or 'reprogram' your native immune system.

2. Normal blood oxygen level in humans is 85mmHg or better. Any lower and you start losing performance- ie, you won't be able to run as far without rest, etc. If your body is sustaining 60mmHg or less and you will need supplimental oxygen.

3. Assuming the drug wasn't filtered and urinated out as waste, you would probably have a very major problem in very short order. The chemical balance of blood is a very delicate one; if for some reason something pressed into the blood that couldn't be shed would shortly affect the blood's ability to carry oxygen to the cells.

For example, some people out there drink ridiculous amounts of water to dilute their blood, which decreases oxygen to the brain, and in turn gives sort of a woozy high. People have died from this. And you can shed water pretty quick through urination.

I imagine in the short term these people would experience lightheadedness, nausea, and would quickly begin to bloat.

[Einna]

Hmm...so if the built up was very gradual and over a long period of time, how long before it becomes lethal?

[Sulis]

Not sure about the other questions, but I do agree with AXJ on the first: If the virus (or whatever) is part of you when you're born, you're probably all right. However, if it was introduced later... THe human body can occcasionally see parts of ITSELF as a foriegn invader, and I think it would be reasonably likely that some outside influence would cause even worse problems with that.

[AXJ]

Hmm...so if the built up was very gradual and over a long period of time, how long before it becomes lethal?

I'm not sure even a hematologist could tell you that with any level of accuracy.

How is it that the body isn't seperating this stuff into its components? Typically any water/fluid components of the drug would be disposed of by your kidneys, leaving behind the active ingredients. I imagine it would be those other ingredients that you'd have to worry about.

[Einna]

The short answer? Fantasy kidney failure.
The longer answer? The second immune system (the toxin) is no longer filtered out and therefore the concentration is building in his blood stream over a long period of time. The drug he's injecting himself with basically smothers whatever it's told to smother (in this case the toxin cells) and stops them from doing anything. But of course, the toxin's still being made, so he's still injecting himself with this stuff to stop the toxin killing him.