I’m phenotyped

th2-dominant

Thanks to the efforts of theSARP researchers and the new era of severe asthma phenotyping, my particular flavor of the disease has finally been described. Drum roll please…………………

It’s called “Long duration Th2 low/mast cell high with remodeling“, asthma.

Sound like a bunch of googly gob? If so, here’s a brief refresher course on T-helper cells.

Our body’s immune system produces a type of white blood cell called a T-lymphocyte, aka T-cells.(They’re called T-cells because they mature in the Thymus gland). Anyway, the T-Lymphocyte’s job is to recognize pathogens (foreign bacteria) and produce what are called cytokines. Cytokines are little hormonal messengers that are responsible for biological effects of the immune system. Cytokines fall into two groups: those that are pro-inflammatory, and those that are anti-inflammatory.The helper T-cells (a type of T-lymphocyte), produce large amounts of two types of cytokines: TH1 and TH2.

TH1 cytokines produced by the helper T-cells produce a pro-inflammatory response. They produce inflammation to kill intracellular parasites (viruses and certain bacteria, such as Mycobacterium tuberculosis – the bug that causes TB). These cytokines also perpetuate any form of autoimmune response, and can cause cell-mediated allergies.

TH2 cytokines produce an anti-inflammatory response, but also promote allergic responses.They counteract the effects of the TH1 cytokines – they have an anti-inflammatory action. But they also help kill extracellular pathogens.The TH2 cytokines induce a pronounced allergic response. When you suffer from allergies, or asthma, especially if it started in childhood, you are likely to be over-producing TH2-types of cytokines, and have a TH1 to TH2 imbalance.

In that regard Im kind of an oddball(so what else is new). I fall into a small subset of people (Cluster 4 ), who despite having life long severe asthma, have a low TH2 response. What makes my asthma so bad, probably has something to do with mast cells. I produce tons of them for some reason, but that’s for another post.

Finally, we get to the “long-duration” and “remodeled” bit. Pretty self explanatory. Means that because Ive has the disease for so long, chances are my airways have undergone some permanent architectural changes, which makes them stiff and not function properly. This of course, is over -simplification of the remodeling process, but you get the idea.

Per Dr Wenzel, even though I don’t have the usual markers of inflammation present in my large airways (high Th2 response) normally seen in severe asthmatics, she believes I do have an inflammatory process going on, but probably a different type and in a different location… more than likely in my smaller airways.

Unfortunately, all the new drugs that have been recently approved by the FDA are designed primarily to treat primarily those with the high Th2 phenotype. But hopefully in the next few years there will be some new therapies for my oddball type as well.

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2 thoughts on “I’m phenotyped

  1. Trust you to be awkward, Stephen. Nothing common, or normal. My consultant said it is better to look for rare variants of common conditions than common variants of rare conditions. So I said “You mean if it is a horse with black and white stripes it is still a horse and not a zebra?” “Yup,” he said. Ask Dr Wenzel if you have a zebra or a horse. (Zebras being rare diseases in the medical world. Probably because they are at the end of the text books and start with Z.)
    Love and gentle hugs
    Kate xxxx

  2. Very cool on the phenotype! I am totally curious where I fit in. Are there new classifications of phenotype from SARP or are these for the SARP 3 peeps?

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