Chen, Marcus Y.

ObjectiveTo describe a 41‐year‐old woman with a history of neonatal onset multisystem inflammatory disease, on treatment with daily subcutaneous injections of 600 mg of recombinant interleukin‐1 receptor antagonist (IL‐1Ra) protein, anakinra, since the age of 28, who presented with golf‐ball size nodules at the anakinra injection sites, early satiety, new onset nephrotic syndrome in the context of normal markers of systemic inflammation.MethodsClinical history and histologic evaluation of biopsies of skin, gastric mucosa, and kidney with Congo‐red staining and proteomic evaluation of microdissected Congo red–positive amyloid deposits by liquid chromatography‐tandem mass spectrometry.ResultsThe skin, stomach, and kidney biopsies all showed the presence of Congo red–positive amyloid deposits. Mass spectrometry‐based proteomics demonstrated that the amyloid deposits in all sites were of AIL1RAP (IL‐1Ra protein)‐type. These were characterized by high spectral counts of the amyloid signature proteins (apolipoprotein AIV, apolipoprotein E, and serum amyloid P‐component) and the amyloidogenic IL‐1Ra protein, which were present in Congo red–positive areas and absent in Congo red–negative areas. The amino acid sequence identified by mass spectrometry confirmed that the amyloid precursor protein was recombinant IL‐1Ra (anakinra) and not endogenous wild‐type IL‐1Ra.ConclusionThis is the first report of iatrogenic systemic amyloidosis due to an injectable protein drug, which was caused by recombinant IL1Ra (anakinra).

Abstract Objectives To describe tracheobronchial disease in patients with granulomatosis with polyangiitis (GPA) and evaluate the utility of dynamic expiratory CT to detect large-airway disease. Methods Demographic and clinical features associated with the presence of subglottic stenosis (SGS) or endobronchial involvement were assessed in a multicentre, observational cohort of patients with GPA. A subset of patients with GPA from a single-centre cohort underwent dynamic chest CT to evaluate the airways. Results Among 962 patients with GPA, SGS and endobronchial disease were identified in 95 (10%) and 59 (6%) patients, respectively. Patients with SGS were more likely to be female (72% vs 53%, P < 0.01), younger at time of diagnosis (36 vs 49 years, P < 0.01), and have saddle-nose deformities (28% vs 10%, P < 0.01), but were less likely to have renal involvement (39% vs 62%, P < 0.01). Patients with endobronchial disease were more likely to be PR3-ANCA positive (85% vs 66%, P < 0.01), with more ENT involvement (97% vs 77%, P < 0.01) and less renal involvement (42% vs 62%, P < 0.01). Disease activity in patients with large-airway disease was commonly isolated to the subglottis/upper airway (57%) or bronchi (32%). Seven of 23 patients screened by dynamic chest CT had large-airway pathology, including four patients with chronic, unexplained cough, discovered to have tracheobronchomalacia. Conclusion SGS and endobronchial disease occur in 10% and 6% of patients with GPA, respectively, and may occur without disease activity in other organs. Dynamic expiratory chest CT is a potential non-invasive screening test for large-airway involvement in GPA.