Thank you both for your concern and suggestions! For me, the onset clearly coincided with the severe exacerbation/hospitalization that led to the diagnosis. The anemia did persist after the sepsis resolved, but, since the hospitalization, it has been mainly mild, with only one transient drop into moderate. My ID doctor actually was the first to mention the connection in passing as he looked at my labs, and I looked into it a bit to see what the mechanism might be (particularly since it predated my first episodes of hemoptysis). It appears that the anemia that can be seen with MAC is not specific to it, but likely an instance of the broader category of "anemia of inflammation" (AKA "anemia of critical illness", if acute, and "anemia of chronic disease" , when chronic). It is seen in association with many inflammatory conditions including acute and chronic infections and autoimmune disease. It is thought to be driven by an immune response, which results in storage or sequestration of iron. This keeps the iron away from a pathogen (MAC apparently likes iron), which is a useful response acutely, but chronically, it also keeps it (quite literally) out of circulation. Anyway, at least for now, the anemia is fortunately not bad enough to worry about. It is just a part of my new normal (and actually less disconcerting than recently discovering I have E. coli in my lungs, which was just weird).