I just got my immunoglobulin subset test results and I'm not happy. IgM: 19.8 (normal range 39.0 - 276.0) IgA: 125.0 (normal range 85.0 - 543.0) IgG: 738.0 (normal range 650.0 - 1650.0) Superficially, this looks like Selective IgM Deficiency (SIgMD) -- low IgM in the context of normal IgA and IgG. Crap. SIgmD is rare, poorly understood, and counter to some of the things immunologists believe about how the immune system works. Theoretically, it shouldn't be possible. Sound familiar? Fortunately, because the tests exist, immunology accepts that SIgMD is a real, not imagined, condition. Unfortunately, it seems there's not a damned thing to be done about it. Take lots of abx, antivirals, antifungals and hope for the best seems to be the currently available suggestion -- according to the internet, at least. Looking at the data a little differently -- My IgA and IgG are normal, but just barely. If I'm doing the math correctly, and I'm not sure I am in my slightly gobsmacked condition, my IgA and IgG are in the bottom 10% of normal. So maybe that could be seen as more like a general immunoglobulin deficiency. In that case there seem to be more treatments, such as IVIG. I'm presently in a mildly shocked state and waiting to hear what my ME/CFS doc has to say about this. As my mind adjusts to this idea, I'd love to hear anything anyone here at PR knows, thinks, or even speculates about my data or immunoglobulins in general. It's just one damned thing after another with this illness, isn't it?