when some foreign particle enters the human body then immune system reacts to it and tries to destroy it, be it anything even an organ from another person. Why immune system does not react to titanium plates-that are attached to fix the broken bones?


I got a titanium plate screwed in my lower jaw that got broken previously. I recently read somewhere that immune system attacks every foreign particle, even transplanted organs that’s why one has to be on immunosuppressants to live with transplanted organs.

In: 3

Your immune system mostly detects the proteins that show up on the outside of living cells. Titanium, obviously, has no such proteins, so there’s nothing for your immune system to sensitize against, at least not in that way.

Metal allergies are the result of [complexes of those metals with proteins already present in your body](https://en.wikipedia.org/wiki/Hapten). This part I’m not certain of, but my guess would be that titanium (which is very non-reactive) doesn’t easily form protein complexes, and thus never gets into a form that your body is sensitive to – a little research suggests that titanium allergies may exist, but are pretty rare.

The immune system reacts to biological markers. Proteins, cell surface markers, various chemicals that bacteria tend to produce…. Things that hostile foreign cells are likely to have.

An organ from someone else has incorrect cell markers so it is flagged as hostile and attacked.

Plant pollen has all sorts of biochemical markers but nothing remotely similar to a human or a bacteria so it sometimes gets flagged too.

Titanium has nothing at all. A blank metallic surface with no discernible chemical traits. Your immune system can’t even “see” it.

This is true for a lot of plastic, ceramic, and metallic foreign materials, but titanium is typically chosen for this application because it has high strength and corrosion resistance.

organs are biological. If they are not genetically yours the body deems them invasive. Titanium forms a strong oxide coating that prevents it from reacting with pretty much anything. This makes it nearly invisible to the body. Other biocompatible substances are similarly ignored by the bodies defenses.

Alloy steel and titanium are non-toxic (many metals are) and when bone encounters titanium it reacts similarly to a bone graft, which is to say it continues to grow properly. Bone would react differently to copper, copper can rupture cell membranes in bacteria! It isn’t about the immune system; this is like getting shot vs getting sick. Your body can’t function if something is inside of it tearing it apart like a molecular weed wacker. Your immune system can fight sick, it can’t and doesn’t fight heavy metal poisoning. In general, it is hard to get a heavy metal poisoning from titanium, it isn’t impossible, but it doesn’t happen from having a surgical implant.

Your immune system is playing a giant game of “Papers please”

When your immune system bumps into something it checks its identification to make sure its recognized. If there is something on the papers (markers on the outside) that it doesn’t recognize or seems suspicious (shiny staples) it throws up the alarm and the rest of the guards come out

There’s a catch here that your body didn’t plan for. If it bumps into something that’s like “gosh i just don’t have papers” it goes “oh alright, you can go” and moves on. This is what lets O- blood be the universal donor, it doesn’t have any markers on it for the immune system to react to. Your body isn’t really sorting things into Self vs Not-Self, its really sorting into Not-Self vs Not-Not-Self

Titanium is similar to O- blood in that its very non-reactive and when your immune system bumps into it to check its papers they get no response and just move on. Its super hard to break titanium bonds to allow it to form compounds so almost all titanium based things are super stable and don’t react, and if you do get them to react *RUN*