Other groups with comparatively low proportions of severe disease were NHL (62 patients [13.7%]) or MPD (48 patients [13.9%]) without recent treatment and CML either without treatment or receiving breakpoint cluster region (BCR)–ABL inhibitors (19 patients [12.7%]), ie, the subgroups least likely to be immunocompromised. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.