Renal amyloidosis: validation of a proposed histological scoring system in an independent cohort

Hoelbeek et al evaluated in a retrospective Dutch multicentre study the value of an amyloid deposit burden score in kidney biopsies with the diagnosis of amyloidosis (of AL-type in 70 cases (75%), AA-type in 19 cases (21%) and “Not Otherwise Specified” in 4 cases (4%)). They applied a formerly proposed scoring system1 with a semi-quantitative scale ranging from 0 to 3 according to the percentage of area filled with amyloid deposits for each of the following compartments: glomeruli, vessels or interstitium, and added a chronic damage score to their analysis. The amyloid score (AS) and the composite scarring injury score (CSIS) predicted eGFR at biopsy-time, but only the AS could predict ESRD progression when over 7.5 in AL-amyloidosis patients. The authors found this approach competent to standardize the nephropathological assessment of such cases and encouraged other teams extending these results to renal AA amyloidosis.
[1] Rubinstein S, Cornell RF, Du L, Concepcion B, Goodman S, Harrell S, Horst S, Lenihan D, Slosky D, Fogo A, Langone A: Novel pathologic scoring tools predict end-stage kidney disease in light chain (AL) amyloidosis. Amyloid 2017, 24:205-11.