It appears that I’m over whatever I had. My nose has stopped running, and my slight cough has resolved as well. I felt a bit under the weather yesterday, but I’m feeling better today—not as good as before this scare, but I’m getting stronger again.
So much of this process is unknown, but a lot is known. One of the things we know is that slightly immature T-cells are responsible for initiating immune responses against viruses. When these T-cells come in contact with other cells that are infected with viruses (or that are otherwise presenting “foreign” chemicals), they do a variety of things that ultimately cause the infected cells to die. But this process takes time, and the infection can spread in the meantime. So, one of the things these immature T-cells do to help with future infection from the same virus is they give rise to more specialized cells. Some of the resulting differentiated T-cells are known as Cytotoxic T-cells (or sometimes CTs, or CD8 cells, where CD refers to a group of proteins on the surface of the cell membrane, deemed Clusters of Differentiation. CTs, or CD8 cells are also sometimes also called T8 lymphocytes, but I’ll just stick to CTs).
CTs are one of many kinds of so-called memory cells; they retain a special chemical affinity (a “memory”) for cells infected with a specific virus, and when the CTs encounter infected cells again, they kill them on the spot—a much faster solution than the slower process that happens the first time infection occurs. This, coupled with other systems, is why once we’ve had a virus, we’re forever immune.
The problem for me is, I don’t really have any T-cells at all. My new immune system is not developed enough to have created any mature T-cells or even any of the slightly immature T-cells needed to initiate the response described above. And that means I don’t yet have any Cytotoxic T-cells from my donor marrow. As CTs are long-lived memory cells, I presumably have circulating in my peripheral blood some of my original, native T-cells that survived the stem cell transplant, but that doesn’t appear to be true. We know this because of the results of my most recent chimerism tests—genetic tests that determine the proportion of peripheral blood cells that are of my genotype versus my donor’s genotype. (Remember that my blood is a chimera right now, like Dictyostelium—part original cells, part donor cells).
Those genetic tests, performed a month ago, show that when considering all of my T-cells, 97% are donor genotype. Those 97% are very immature (too immature to give rise to CTs), and the remaining 3% are what’s left from my former immune system. And while this 3% no doubt includes mature T-cells, and some CTs, they just aren’t very clinically effective for most people (so says my physician). Hammered from the chemotherapy of the transplant? The radiation? Too few to mount a defense? I’m not sure, but they’re impact is apparently thought to be minimal in any event.
But something has changed. I had these symptoms, and now they’re gone. Maybe I beat a virus somehow; maybe it was allergies. I guess I don’t care too much, except from an academic position. But one thing is certain: It couldn’t have been that crystal I shoved up my butt. I only did that an hour ago.