FWIW, I've always had BMBs in which my bone marrow cellularity is around 2-5%. The last one, in January of this year, was 5% and it was the highest I've ever had. Various hematologists have explained this to me accompanied by a theme of, "Well, you're making blood cells somewhere. You're here. We just can't find where you're making these cells." I've been having these BMB cellularity results for almost 44 years now. By now, I just say to myself, "What - me worry?"
Margaret