A clinicopathological analysis in a large cohort of Chinese patients with renal amyloid light-chain amyloidosis.

BACKGROUND: The aim of the study is to investigate the association between clinical and pathological features in a large cohort of Chinese patients with renal immunoglobulin light-chain amyloidosis (AL).

METHODS: A series of 186 patients with renal AL amyloidosis diagnosed between 1990 and 2011 were retrospectively reviewed. The extent of amyloid deposition in glomeruli, blood vessels and tubulointerstitium were evaluated semiquantitatively. The renal amyloid load was defined by the sum of glomerular, vascular and interstitial deposits. The associations between the clinical manifestations and pathological features were analyzed.

RESULTS: The extent of glomerular amyloid deposition was positively correlated with the level of proteinuria. Patients with codeposition of amyloid and immune complexes (ICs) in glomeruli had higher levels of proteinuria than those without ICs. Advanced glomerular amyloid deposition was an independent pathological factor associated with renal insufficiency at diagnosis. The degree of vascular amyloid (VA) deposition was positively correlated with cardiac involvement and hepatic involvement. Patients with AL-κ showed a higher prevalence of hepatic involvement and more severe VA deposition than patients with AL-λ. High renal amyloid load independently predicted the increased risk for overall death after adjusting for recognized confounders.

CONCLUSIONS: The degree and localization of amyloid deposits in the kidney of AL patients were associated with the degree of proteinuria and renal insufficiency, as well as extrarenal organs involvement. There were some differences between AL-κ and AL -λ in clinical and pathological characteristics. The renal amyloid load was an independent predictor for overall mortality.