Kidney Week

Abstract: TH-PO666

Lupus Nephritis Histopathological Classification System: A Questionnaire-Based Survey of the Renal Pathology Society (RPS)

Session Information

• Lupus Nephritis: Clinical, Outcomes, and Therapeutics
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Uzzo, Martina, Universita degli Studi di Milano-Bicocca Scuole di Specializzazione, Milano, Lombardia, Italy

Martina Uzzo, MD

• Haas, Mark, Cedars-Sinai Medical Center, Los Angeles, California, United States

Mark Haas, MD, PhD

• Jayne, David R.W., University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

David R.W. Jayne, MD, MBChB

• Lightstone, Liz, Imperial College London Faculty of Medicine, London, London, United Kingdom

Liz Lightstone, MBBS, PhD

• Parodis, Ioannis, Karolinska Institutet, Stockholm, Stockholm, Sweden

Ioannis Parodis, MD, PhD

• Rovin, Brad H., The Ohio State University, Columbus, Ohio, United States

Brad H. Rovin, MD, FASN

• Seshan, Surya V., Weill Cornell Medicine, New York, New York, United States

Surya V. Seshan, MBBS

• Akilesh, Shreeram, University of Washington School of Medicine, Seattle, Washington, United States

Shreeram Akilesh, MD, PhD

• Fogo, Agnes B., Vanderbilt University Medical Center, Nashville, Tennessee, United States

Agnes B. Fogo, MD

• Bajema, Ingeborg M., Universitair Medisch Centrum Groningen Pathologie en Medische Biologie, Groningen, Groningen, Netherlands

Ingeborg M. Bajema, MD, PhD

Background

The updated 2018ISN/RPS histopathological classification on kidney biopsy is widely used for prognosis and treatment decisions in lupus nephritis (LN). Due to the success of new targeted agents, there is ongoing discussion about the need for updating existing classification systems. A survey to assess the current use of the 2018ISN/RPS classification system in everyday practice was conducted on behalf of the RPS.

Methods

An online survey was sent between September 27^thand October 24^th2023 to active members of the RPS. The survey contained multiple-choice and open-ended questions; results were analyzed anonymously.

Results

185 of 562 RPS members replied to the questionnaire, mostly pathologists (97%). 120(65%) participants encounter >20 LN biopsies per year, while 13% <10. Nearly 90% discuss biopsy results in multidisciplinary meetings, involving both pathologists and clinicians. The 2018ISN/RPS classification is used in most cases(92%) and 90% of the pathologists include NIH activity/chronicity indices in biopsy reports, although concerns about workload, reproducibility and clinical utility were raised. The average grade on the utility of the 2018ISN/RPS classification and activity/chronicity indexes were 8(IQR 7-9) and 7(IQR-9) on a scale from 0(not useful) to 10(extremely useful). Pathologists rated clinicians' understanding of kidney biopsy reports with an average score of 8(IQR 7-9) on a scale from 0(no understanding) to 10(complete understanding). Suggested improvements of the 2018ISN/RPS classification involved the introduction of new parameters (focus on extraglomerular involvement, laboratory, clinical features), biomarkers (CD68+ staining for endocapillary hypercellularity, EXT1/2 immunostaining), standardization and simplicity. Clearer definitions were requested for class III vs IV, segmental sclerosis vs fibrous crescents, the role of globally sclerosed glomeruli and lupus-like entities.

Conclusion

Our survey shows the 2018ISN/RPS classification is widely used in everyday practice by pathologists, and well known by clinicians. The results obtained by the RPS survey acknowledge the need for ongoing refinement to facilitate targeted treatment decisions, particularly considering evolving phenotypes and therapeutic advancements in LN.