[1] The disease is caused when a person's antibody-producing cells do not function properly and produce abnormal protein fibers made of components of antibodies called light chains.
[6] Other manifestations of kidney involvement may include protein loss in the urine, low albumin levels in the blood and secondary hyperlipidemia (nephrotic syndrome).
Early heart involvement in AL amyloidosis may present as low voltage electrical rhythms on an electrocardiograph, concentric left ventricular hypertrophy and diastolic dysfunction.
Further signs of cardiac involvement in AL amyloidosis include heart arrhythmias (bradycardia, ventricular tachycardia) which may necessitate pacemaker or implantable defibrillator placement and reduced contractility of the atria, with the associated risk of atrial blood clots.
[9] Diagnosis of AL amyloidosis requires identification of amyloid deposits within a tissue sample and confirmation of a plasma cell disorder.
[6][10] A fine needle aspiration (FNA) may be done of the abdominal fat pad (which commonly contains amyloid deposits) to aid in the diagnosis of AL amyloidosis.
[4] On microscopic exam of biopsy specimens, amyloid deposits appear green ("apple-green birefringence") when stained with Congo Red dye and viewed under polarized light.
[4] The precursor protein that is forming the amyloid fibrils may be identified using immunohistochemical studies such as immunofluorescence or immunostaining, immunogold electron microscopy or mass spectroscopy (which is not widely available).
[12][13] Other treatments can involve application of chemotherapy similar to that used in multiple myeloma, which targets the plasma cells responsible for producing the misfolded light chain proteins.
[13] The most widely used regiment, and first line therapy, for those ineligible for a stem cell transplant is cyclophosphamide, bortezomib and dexamethasone (CyBorD) with daratumumab added.