Of the three cases described (PMID 22616969, 28279286, Martires et al. Constrictive bronchiolitis and organizing pneumonia associated with rituximab. Chest, 2013. 144 (4_MeetingAbstracts): p. 671A (unpublished as of July, 2019)), all three had a Hx of lymphoma. In none of these three cases were immunoglobulin levels mentioned. As rituxumab may induce hypogammaglobilinemia, post-rituximab bronchiolitis/BO may reflect pulmonary expression/complications of acquired immunoglobulin deficiency rather than be a direct toxic effect of the medication