The immune system has many branches, and you can effectively deplete one branch of the immune system while preserving the other branches to fight infection. For example with MS a very effective treatment is CD20+ B cell suppression, as rituximab does. For many people diagnosed with MS this has been effectively a "cure," in the sense that while they need to continually deplete their CD20+ B cells, their disease doesn't progress in any meaningful way, and their immune systems remain largely able to fight infection.
So we don't need to wholesale "turn down" the entire immune system for many autoimmune diseases. Rather, we need to surgically target specific parts of it and either suppress those parts or modify their behavior. Given the success we've seen with ritixumab and MS I'm more optimistic about our prospects for finding effective treatments for autoimmune conditions.
No, the immune system is not controlled by our microbiome. The microbiome interacts with, and modulates the immune system in various ways, but it's hardly "controlling" it. There are germ-free animal models with sterile guts, which demonstrate that you can live without a microbiome - of course not 100% healthy, but they can still live and reproduce.
The immune system is modulated by a lot of things: circadian rhythm, environmental stress, nutrients, etc. Yes, the gut microbiome is one of them. But let's be a bit more nuanced than Joe Rogan or The Liver King.
> pro-inflammatory drugs can induce people to become depressed, which suggests a causative link. In one seminal study published in the New England Journal of Medicine, Miller and his colleagues conducted a double-blind study of 40 cancer patients undergoing treatment with interferon-alpha, an inflammatory cytokine.
> Though none of the patients had depression to begin with, the inflammatory agent had a striking effect: Many became depressed, a finding that has been consistently replicated.
Vitamin C is essential and gets consumed by the body and needs to be replenished. For example during sickness the Vitamin C consumption is higher which could lead quickly to low levels.
There is evidence that things that reduce systemic inflammation help with depression. Fish oil, or more generally a balanced omega-3/omega-6 intake is one example. Curcumin is another. However the effects are modest, which is probably to be expected with a condition as diverse as depression.
Recently (and still in many cases) "turn down the immune system" was the treatment for most cancers. Of course, the purpose of anti-cancer drugs isn't to turn down the immune system. It just happens that the side effect of drugs that target cancer cells also target other rapidly-dividing cells like hair, endothelial, and immune cells.
In fact, chemotherapy drugs like Methotrexate are prescribed - at lower doses than for cancer patients - to people with Lupus and other autoimmune diseases.
There are similar challenges with cancer and autoimmune diseases, so progress in one might help progress in the other.
From the article: "They are now working to find ways to deliver these molecules safely and effectively to people." This is a challenge for many potentially effective cancer treatments as well.
Just as antivirals are actually ‘stop cell division’
Neither of which inspire any confidence