What is inflammation? I recall the Latin based description of inflammation that I learned in Medical School. Inflammation is heralded by pain (dolor), redness (rubor), heat (calor) and swelling, (tumor). Rubor, dolor, calor and tumor. This gives a nice image, a good presentation of what we can expect clinically from someone who is inflamed. We have all experienced this course personally as a small cut becomes red and painful, warm to the touch. The tissues beneath the cut seem to swell- and over time, if all is in balance, the symptoms redress; the swelling becomes less pronounced, the pain slowly seems to abate; the warmth slowly gives way to our normal skin temperature and contour.
In this example, we have witnessed an appropriately balanced and functioning immune system; one which is activation is tempered by duration and extent of the inflammation, and finally the ability to know when to shut things down, when to turn off.
Have you been exposed to a flu virus recently? I hope not, but if you were I hope your symptoms were short lived. Recall that initially you may have felt the onset of the illness with some malaise, body aches and pains. This resulted from a generalized immune response against the virus, one in which the immune system assumed a “take no prisoners” approach, and mounted a non-specific whole body state of inflammation in the hope of ultimately preserving you, the host. As the specifics of the infection became known to the immune system, a more targeted approach was launched, with inflammatory cells directed to your sinuses (runny nose!) or productive cough (lungs!). As the molecular battle between the virus and our immune system ran its course and the viral infection was defeated, the tissues were instructed to decrease the additional blood flow, to turn off the inflammatory cells, and to remodel to their original function, shape and appearance.
This is an example of an infectious cause of a inflammatory response. The immune system also responds to foods, toxins, pollutants and cigarette smoke.
It can respond to dust, cat fur, or medications. The immune system can also be activated to our own tissues, our own cells, or our own DNA. This is an autoimmune response, one in which our immune system has lost the ability to identify and discern our own tissues from the invading outside world. The same battle is set up, but the target of the inflammatory response is our own body, our own healthy cells.
There is one final point to recall as we continue our discussion on inflammation. The immune system, which includes the cells, communication signals, and the toxic chemicals used in molecular warfare, responds to only one thing. It responds to molecular signals. And the immune system has only one recourse with which to combat these “dangerous” molecular signals; it responds with an inflammatory reaction.
So stay tuned to my next blog. There we will look at the ways that dangerous molecular signals are identified, how the immune system sounds the inflammatory “alarm”, and the armamentarium of toxic munitions at our disposal.
Dr. Scott Resnick