Yes it's our old friend IGM. What is it? "IgM is by far the physically largest antibody in the circulation" says Wikipedia. "The class of antibodies found in circulating body fluids and the first antibodies to appear in response to an initial exposure to an antigen" according to yourdictionary. "IgM is a large pentameric structure, whose higher molecular weight tends to confine it within blood vessels" says gpnotebook.
Immunoglobulin M (to give it it's full name) is often held up to be the villain of the piece to those of us who suffer from Waldenstroms. WM affects plasma cells, which develop from white blood cells called B-lymphocytes, or B cells. Some of these B cells become plasma cells, which make, store, and release antibodies.In WM abnormal plasma cells multiply out of control. They invade the bone marrow, lymph nodes, and spleen and produce excessive amounts of IgM. As we've seen IGM is a huge molecule, the "buster blood vessel" of the antibody world, and it's therefore not advisable to have too much of it. As the plasma cells pump out this stuff your blood begins to get thicker and thicker; it's called hyperviscosity and it's not much fun.
"Confusion and mental status changes result from the increased viscosity of the blood and decreased cerebral blood flow. This sludging leads to segmental dilatation of retinal veins and retinal hemorrhages. Mucosal bleeding may occur from prolonged bleeding time caused by myeloma proteins interfering with platelet function.
Cardiopulmonary symptoms such as shortness of breath, hypoxemia, acute respiratory failure, and hypotension also result from this sludging of blood and decreased microvascular circulation." (eMedicine)
Before I knew I had WM my IGM soared unchecked and my blood started to turn to treacle. I was sluggish and lethargic; I woke up everyday with a headache that I just couldn't seem to shake off; the slightest bit of physical exertion left me short of breath and dizzy. I was unaware that I was terribly ill. One of the abiding memories I have of that time is trying to play a game of football with my daughter on the beach and having to stop not only for a breather but a full-scale lie down after only a couple of minutes. The treatment for acute hyperviscosity is called plasmapheresis. I've described in an earlier post how this involved the insertion of an unfeasibly large needle into my left arm through which my gloop filled blood was passed to a large centrifuge. I felt instantly better, clear-headed and much more alert than previously. My joy at the instant success of this treatment was tempered rather when it was explained to me that this was only treating the by-product of my cancer and not the cancer itself; that of course would need chemotherpay. Bollocks. I'd thought I might get away without needing it. No such luck.
I and all other WM sufferers obssess about our IGM levels. We have regular blood tests to monitor what it's doing. WM is a disease that presents differently in every individual it affects so that we all become symptomatic at different levels of IGM in our system. For some it's very low, others can seem to get on quite happily at astonishingly high levels. For all of us it's the way we trace the progress of our disease and the effectiveness of the treatments we take for it. After my 6 months of chemotherpay I have watched happily as my IGM levels slowly but steadily fell month on month. It had to happen I suppose but now, just over 3 years down the line with a nice partial remission going on, it's started to creep up again. It's just one reading, and it might be a "blip." Watch this space.
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