@sheila7a Dr. Hewitt from NJH has a video where she briefly mentions the side effect of lowered white blood cells to the antibiotics. She references it to say before doing any more complicated testing for “bad things” just go off the antibiotics and recheck first, as lowered white blood cells is a known side effect of treatment and not necessarily a sign of something more nefarious, particularly if one’s white blood cell count was fine before they started the antibiotics. I don’t recall her saying if it’s one of the antibiotics or the combined effect of the antibiotics, or what happens next in terms of treating NTM but she did raise the specific scenario of lowered white blood cells as a known side effect. Not sure this is helpful, but at least you know you are not alone on this.