Fodder for thought about the immune system

Interesting things about the immune system:

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Popular culture also its myths. Take the immune system. Please. It is not a bicep that can be made stronger with a little exercise. It is a complex network of cells and proteins. There are antibodies (IgG (with five subtypes, IgM, IgA, IgE), the complement pathway, polymorphonuclear cells, monocytes, lymphocytes in a profusion that rivals beetles. God, I think, has an inordinate fondness for lymphocytes. There is the Toll system, the cytokines and lymphokines, the non-specific defenses like cilia and mannose binding lectin and on and on and on.

I have a journeyman’s understanding of the immune system, what is needed to understand why a given patient has an infection, although there is little I can do to reverse the immunologic defects: abnormal antibodies from Waldenström’s or low mannose binding lectin levels from liver disease are not amenable to clinical intervention. The most interesting discoveries concerning the immune system over the last few year has been the elucidation of the many polymorphisms in the immune system that can increase or decrease the risk of a variety of infections.

The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings.

Often what determines health or infection, life or death, is a single amino acid substitution, say, in a Toll like receptor or the structure of our snot.

Of course these variations in the immune system are not absolute risks, they are relative risks. Health and illness are complex and a career medicine and infection control has continually emphasized that it is rarely one thing that leads to health or illness. It is the confluence of multiple factors, death by a thousand cuts.

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