Anakinra-Associated Systemic Amyloidosis

Abstract

Objective: To 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.

Methods: Clinical 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.

Results: The 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.

Conclusion: This is the first report of iatrogenic systemic amyloidosis due to an injectable protein drug, which was caused by recombinant IL1Ra (anakinra).

Figure 1.. The clinical and histological presentation of systemic amyloidosis.

Panel A. Nodular masses at the sites of anakinra injections on the abdomen (arrows). Panel B. Skin biopsy with extensive subcutaneous Congo red-positive amyloid deposits in an interstitial and perivascular distribution. Panel C. The apple-green birefringence of the Congo red-stained cutaneous amyloid under polarized light. Panel D. Kidney biopsy with Congophilic deposits in the mesangium and a capillary wall. Panel E. Acellular periodic acid-Schiff (PAS)-negative amyloid deposits in the glomerulus (PAS-stain). Panel F High magnification transmission electron microscopy (TEM) image of amyloid deposits that revealed randomly oriented –fibrils(X50,000).

Figure 2.. Mass spectrometry-based proteomics identifies IL1RA (Anakinra)-associated amyloid deposits in the skin, stomach, and kidney.

In Panels, A to C, Congo red-positive (CongoRed Pos) amyloid deposits in the skin (Panel A), stomach (Panel B), and kidney (Panel C) were microdissected under ultraviolet light. Panel D: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of CongoRed Pos and Congo red-negative (CongoRed Neg) areas in the skin, stomach, and kidney biopsies. Proteins in the blue box indicate the amyloidogenic recombinant IL-1Ra protein (anakinra) (dual yellow/blue star) and the three universal amyloid signature proteins (blue stars). Numbers in green boxes indicate the total number of MS/MS spectra matched to the protein in the corresponding biopsy and are a semi-quantitative measure of abundance. High spectral counts of the amyloid signature proteins (Apolipoprotein E, Apolipoprotein A-IV, and serum amyloid P-component) and the amyloidogenic IL1RA protein (anakinra) are present in CongoRed Pos areas and absent in CongoRed Neg areas. Panel E. The amino acid sequence difference of recombinant IL-1Ra (anakinra), lacking 24 N-terminal amino acids compared to endogenous IL-1Ra. The size difference between wild-type and recombinant IL-1Ra generated MS/MS spectra identifies amyloid in the CongoRed Pos tissues as recombinant (anakinra).