Lupus Nephritis. Ingeborg Bajema

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1 Lupus Nephritis Ingeborg Bajema

2 Lupus nephritis: the basics Up to 60% of patients with SLE develop lupus nephritis during the course of their disease Lupus nephritis is associated with considerable morbidity and poor survival, in particular in case of ESRD The diagnosis, pathogenesis and treatment of lupus nephritis are intricately linked The histopathological findings in lupus nephrits vary considerably; classification of lupus nephritis is essential for treatment decisions 2 22-Sep-17

3 Lupus nephritis: IF and EM 3 22-Sep-17

4 Lupus nephritis classification systems Present in < 50% of glomeruli Acute or Chronic? Present in > 50% of glomeruli Acute or Chronic? Segmental / Global? 4 22-Sep-17

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6 Glomerular lesions in lupus nephritis By LM, we will not be able to identify the true nature of some of the cells in lesions like the ones depicted here There is interobserver disagreement on cells and lesions we think we can characterize with some degree of confidence 6 22-Sep-17

7 Interobserver (dis)agreement No statistically significant effect of level of experience on outcome

8 Segmental or Global? 8 22-Sep-17

9 Segmental or global?

10 Clinical significance of segmental/global? Haring et al. JASN 2012

11 Leiden lupus nephritis meeting, May 2016 Aim: To improve problematic definitions that form the basis of the LN classification and thereby increase interobserver agreement between nephropathologists worldwide who apply these definitions to classify lupus nephritis Ingeborg Bajema, Suzanne Wilhelmus, Charles E. Alpers, Jan Bruijn, Robert B. Colvin, Terry Cook, Vivette D Agati, Franco Ferrario, Mark Haas, J. Charles Jennette, Kensuke Joh, Cynthia C. Nast, Laure-Hélène Noël, Emilie Rijnink, Ian SD Roberts, Surya V. Seshan, Sanjeev Sethi, Agnes Fogo Sep-17

12 Leiden lupus nephritis meeting, May 2016 Aim: Our eventual aim is to improve the lupus nephritis classification using an evidence based approach, but refining the definitions first is necessary because they form the essential elements on which the classification is based. Two-level approach: 1. Adjust definitions for inconsistencies, vagueness, omissions. Minor changes to thresholds if evidence to do so already exists; claryfing details; providing useful examples that illustrate difficult issues 2. evidence-based multi-center study, involving scoring of separate parameters, relation to outcome, results used to guide possible modifications of the existing classification system Sep-17

13 Mesangial lesions in LN How much hypercellularity in how many glomeruli? How many cells, and how to combine with matrix expansion (cut-off) If only mesangial cells: hyperplasia If not only mesangial cells: endocapillary hypercellularity?

14 Pictures drawn by Prof C. Jennette

15 Considerations on mesangial lesions in LN Increase threshold of mesangial hypercellularity from 3 to 4 cells/mesangial area (cf IgAN) Discussion of inflammatory cells in mesangium postponed to level 2

16 Endocapillary lesions in LN Endocapillary proliferation Types and numbers of cells involved: unclear Amount of lumen reduction: unclear Role of endothelial cells: unclear

17 Considerations of endocapillary lesions Replace the term endocapillary proliferation by endocapillary hypercellularity The cut-off level for: - number of inflammatory cells - extent of capillary luminal narrowing - role of endothelial cell swelling, needs to be defined in a level 2 exercise.

18 Segmental / global lesions Clinical significance: questioned Interobserver variation: large Uncertain how to combine endocapillary lesions and extracapillary lesions into the segmental / global distinction Part of the original discussion to indicate vasculitic-like lesions lost Consideration: remove segmental/global connotations

19 activity/chronicity A, C and A/C is an insufficient discriminator Consideration: Move back to the NIH Activity/Chronicity Indeces

20 Variations on a theme

21 Summary Pathogeneic background in relation to histological variability Renal outcome Classification system

22 Clinical and Histopathologic Characteristics associated with Renal Outcomes in Lupus Nephritis Fibrinoid necrosis 1.04 ( ) Non-white race 2.23 ( ) HR (95% CI)* PREDICTORS n = 47 n = 21 ESRD Fibrinoid necrosis 1.08 ( ) Fibrous crescents 1.09 ( ) IF/TA 25% 3.89 ( ) Baseline egfr 0.98 ( ) Non-white race 7.16 ( ) CONCLUSION In the assessment of the risk of progressive renal dysfunction, the LN classification should include an index of evidence based predictors in conjunction with clinical findings. Emilie Rijnink et al, 2017