• Question: How would a disease cause the body to turn against itself?

    Asked by anon-252718 to Tony, Spyros, Melanie on 5 May 2020.
    • Photo: Melanie Krause

      Melanie Krause answered on 5 May 2020:

      Thank you! 🙂
      There are a number of ways..
      Some diseases like allergies or autoimmune diseases are caused by the immune system being over-active. In these cases the body can’t properly recognise between what is dangerous (e.g. a virus) or what is harmless (e.g. a grass pollen) and shoots up an immune response that is much stronger than what would be needed.. these are allergies.

      For autoimmune diseases there are different ways, but essentially the body also thinks something is dangerous that is not and attacks part of the body.. these people often need to take medication to dampen the immune system.

      Another way is how for example a virus hijacks cells and kind of turns them into zombies by manipulating their immune response, there protein production and their movement by depositing their own genetic information that the cell then ‘reads’ and takes as a command.

      There are definitely more ways than these but those were the first that came to my mind 🙂

Comments

  • Photo: Gabriela

    Gabriela commented on :

    Melanie has given an excellent description of circumstances where the body turns against itself. I am interested in diabetes and one form of diabetes, called type 1 diabetes, results from the body turning on itself. There are special cells in your body that make a protein called insulin. Insulin helps to regulate sugar balance in the body. In type 1 diabetes, the body mistakes the cells that make insulin for something that shouldn’t be in the body, and the immune system is activated to attack the insulin producing cells, leading to the death of these cells. The loss of these cells means no insulin is produced and so sugar balance cannot be maintained, resulting in diabetes.

    • Photo: Melanie

      Melanie commented on :

      Definitely true! Thanks for the add on! I’m not a diabetic researcher …I had this one in mind as one of the classic examples but I thought I’d leave it to an expert like you 😉

  • Photo: Eleanor

    Eleanor commented on :

    Melanie and Gabriella have given great answers for this. But what always interested me is why my patients (I’m a vet) would be OK for ages then start to show the signs of auto-immune disease (where the body starts to attack itself). There are lots of things that can influence that like hormone and genetics (for instance, auto-immune disease is more common in females). But ultimately, the immune system has switched from tolerating stuff that should be there (‘self’) to attacking it (because it perceives it as ‘foreign’). Why? The proper answer to that would go on for pages but my simple clinician’s summary is that usually the switch is commonly triggered by one of three things:

    1) a change in the body means the immune system can ‘see’ something it didn’t previously see, and which it therefore interprets as ‘foreign’. That can happen where there is tissue damage for any reason, including inflammation.
    2) Something external to the body causes proteins in the body to mimic something foreign. Commonly that can be because of medicines – the classic example is one of the early kinds of antibiotic called sulphonamides.
    3) The third reason is a bit like (1) in that the immune system gets to see something for the first time – but in this case it is the bugs that are quite normal in our body, classically the gut. For instance, a ‘simple’ gut infection can cause the gut wall to leak so that the immune system ‘sees’ the normal bacteria that live in our guts for the first time. They react (after all, the immune system is designed to fight microbes) but in this case it is an over-reaction as it is quite normal to have a gut full of ‘friendly’ bacteria. The inflammation causes more leakiness and more inflammation. This seems to be the problem in conditions like Chrone’s disease.

    I hope that helps!