High frequency of amyloid lymphadenopathy in uremic patients
Amyloid lymphadenopathy has only been reported in case report form, or in small groups of patient groups within large series. We believe that amyloid lymphadenopathy is common in uremic patients, and thus designed this study to determine the frequency of this condition in hemodialysis patients, and to assess its types and patterns. We reevaluated 46 uremic patients' lymph node biopsies for amyloid deposits. We also immunohistochemically identified the protein origin of these deposits using Amyloid A, kappa, lambda, beta2 microglobulin, and transthyretin antibodies. Histopathologically, we observed for vascular involvement, follicular deposition, and diffuse deposition. We detected amyloid deposits in 10 of the 46 (22%) patients' lymph nodes. The patterns of deposition were vascular involvement alone in six specimens, vascular involvement plus follicular deposition in three, and vascular involvement plus diffuse deposition in one specimen. Amyloid AA type protein was present in seven nodes, beta2 microglobulin-related amyloid in two nodes, and immunoglobulin-derived protein (AL) in one node. We assessed these 10 patients for causes of end-stage renal disease (ESRD) and other conditions that might relate to amyloidosis. The cause of ESRD in the seven patients with AA amyloid were renal amyloidosis secondary to Familial Mediterranean Fever in four, glomerulonephritis in one patient who had bronchiectasis and Castleman's disease, unknown in one patient who had bronchial asthma, and pyelonephritis in one patient who had no characteristics that could be linked with AA type amyloidosis. The causes of ESRD in the two individuals with beta2 microglobulin-related amyloidosis who had been on long-term hemodialysis were pyelonephritis and glomerulonephritis. The cause of ESRD in the patient with AL type protein was glomerulonephritis, and this patient had no systemic disease. We conclude that amyloid lymphadenopathy is, indeed, common in uremic patients. Amyloid type AA is the most prevalent form of amyloid protein in uremic patients, but amyloid type does not always correspond with underlying cause of renal failure, or with the presence of systemic disease.