Clinicopathologic predictors of renal outcomes in light chain cast nephropathy: a multicenter retrospective study

Blood. 2020 May 21;135(21):1833-1846. doi: 10.1182/blood.2019003807.

Abstract

Light chain cast nephropathy (LCCN) in multiple myeloma often leads to severe and poorly reversible acute kidney injury. Severe renal impairment influences the allocation of chemotherapy and its tolerability; it also affects patient survival. Whether renal biopsy findings add to the clinical assessment in predicting renal and patient outcomes in LCCN is uncertain. We retrospectively reviewed clinical presentation, chemotherapy regimens, hematologic response, and renal and patient outcomes in 178 patients with biopsy-proven LCCN from 10 centers in Europe and North America. A detailed pathology review, including assessment of the extent of cast formation, was performed to study correlations with initial presentation and outcomes. Patients presented with a mean estimated glomerular filtration rate (eGFR) of 13 ± 11 mL/min/1.73 m2, and 82% had stage 3 acute kidney injury. The mean number of casts was 3.2/mm2 in the cortex. Tubulointerstitial lesions were frequent: acute tubular injury (94%), tubulitis (82%), tubular rupture (62%), giant cell reaction (60%), and cortical and medullary inflammation (95% and 75%, respectively). Medullary inflammation, giant cell reaction, and the extent of cast formation correlated with eGFR value at LCCN diagnosis. During a median follow-up of 22 months, mean eGFR increased to 43 ± 30 mL/min/1.73 m2. Age, β2-microglobulin, best hematologic response, number of cortical casts per square millimeter, and degree of interstitial fibrosis/tubular atrophy (IFTA) were independently associated with a higher eGFR during follow-up. This eGFR value correlated with overall survival, independently of the hematologic response. This study shows that extent of cast formation and IFTA in LCCN predicts the quality of renal response, which, in turn, is associated with overall survival.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acute Kidney Injury / complications*
  • Acute Kidney Injury / pathology
  • Acute Kidney Injury / therapy
  • Aged
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Combined Modality Therapy
  • Female
  • Follow-Up Studies
  • Humans
  • Immunoglobulin Light Chains / blood
  • Kidney Diseases / etiology
  • Kidney Diseases / mortality*
  • Kidney Diseases / pathology
  • Male
  • Multiple Myeloma / complications*
  • Multiple Myeloma / pathology
  • Multiple Myeloma / therapy
  • Prognosis
  • Retrospective Studies
  • Stem Cell Transplantation / adverse effects
  • Stem Cell Transplantation / mortality*
  • Survival Rate
  • Transplantation, Autologous

Substances

  • Immunoglobulin Light Chains