AL-Kappa Primary Amyloidosis with Apolipoprotein A-IV Deposition

Area of Science:

• Nephrology
• Hematology
• Pathology

Background:

• Renal amyloidosis presents with edema, malaise, and hypotension.
• Distinguishing amyloid subtypes is crucial for prognosis and treatment.
• Smoldering myeloma can coexist with systemic amyloidosis.

Observation:

• A 70-year-old woman presented with symptoms suggestive of renal amyloidosis.
• Laser microdissection mass spectrometry identified apolipoprotein A-IV as the predominant amyloid type.
• M-protein became positive, and bone marrow biopsy revealed smoldering myeloma.

Findings:

• The patient developed heart failure despite treatment with bortezomib and dexamethasone.
• Western blotting confirmed amyloid light-chain kappa (ALκ) amyloidosis was present from the onset.
• Congo red staining was positive in bone marrow plasma cells, differentiating it from the myeloma itself.

Implications:

• Apolipoprotein A-IV amyloidosis can be aggressive and lead to severe complications like heart failure.
• Coexistence of smoldering myeloma and ALκ amyloidosis presents diagnostic and therapeutic challenges.
• Further research is needed to understand the pathogenesis and treatment strategies for apolipoprotein A-IV amyloidosis.