**8. Conclusions**

In conclusion, the precise identification of key glomerular, tubulointerstitial and vascular lesions remain incompletely understood in terms of pathogenesis and prognostic effect. The ISN/RPS classification improved the knowledge of different patterns of LN lesions, and validation studies have shown new emerging morphological data to be further investigated and included in the classification [8, 12, 35]. Most nephrologists find an assessment of activity and chronicity

History: Patient with erythema and scaling in the face, lymphocitopenia, anemia, proteinuria of 2g/24h, microhematuria, serum creatinine of 1,8 mg/dl. Anti-dsDNA>200 UI, ANA 1/1600.

Renal biopsy

Macroscopy: 3 fragments of renal biopsy measuring each 1cm long. One fragment fixated in Duboscq-Brazil was sent to LM, 1 frozen fragment was sent to IF using anti-IgG, IgA, IgM, C1q, C3, Fibrin, κ and λ conjugates, 1 fixated in glutaraldehyde 2,5% sent to EM.

Light Microscopy: Renal biopsy showing the cortical with 30 glomeruli, all with large size and mesangioendothelial heavy hypercellularity and moderate exsudate of polymorphonuclear neutrophils; some peripheral capillary loops show bulky hyaline deposits obliterating capillary lumens (wire loops). In 6 glomeruli there are small segments fibrinoid necrosis, nuclear debris and fibrin deposits, with overlying small cellular crescents. Two glomeruli are globally sclerosed surrounded by tubular atrophy and mild interstitial fibrosis. There is also a heavy interstitial edema and inflammatory infiltrate of mononuclear cells with degenerative changes of tubules. The vessels are unremarkable.

Immunofluorescence: Presence of diffuse granular deposits in the mesangium and capillary loops of IgG (3/3+), IgA (2/3+), IgM (1/3+), C1q (3/3+), C3 (2/3+), Fibrin (2/3+), κ and λ (2/3+). There were deposits in the tubular basement membrane and peritubular capillaries of IgG and C1q (2/3+). There were no deposits in the vessels.

Electron microscopy: Presence of mesangial, subendothelial and tubular basement membrane electrondense deposits.

Renal biopsy diagnosis: Lupus nephritis characterized by diffuse proliferative glomerulonephritis with 20% of segmental necrosis, 20% of cellular crescents and 6,6% of global glomerular sclerosis. Intense lymphomononuclear tubulointerstitial nephritis with focal tubular atrophy and interstitial fibrosis. Normal vessels.

**31**

**Author details**

Rosa Marlene Viero\* and Daniela Cristina dos Santos

\*Address all correspondence to: rosa.viero@unesp.br

provided the original work is properly cited.

Department of Pathology, Botucatu Medical School, UNESP, Botucatu, SP, Brazil

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Lupus Nephritis: Renal Biopsy Guiding the Clinician DOI: http://dx.doi.org/10.5772/intechopen.97169*

be carried out to validate the new proposal [38].

The authors declare no conflict of interest.

Medical School for all the learning that allowed this work.

**Acknowledgements**

**Conflict of interest**

indices useful, and the biopsy reports should include routinely, with a detailed description of the types of active and chronic lesions and proportion of glomeruli affected (**Figures 1**–**3** and **Box 1**). Despite these unresolved controversies, active lesions versus chronic lesions, in addition to class of LN, influence response to therapy. The ISN/RPS recently presented a consensus report from a meeting of an international nephropathology working group in 2016. Briefly, they proposed new definitions for mesangial hypercellularity and different patterns of crescents; endocapillary proliferation was replaced by endocapillary hypercellularity, the IV-S and IV-G subclasses were eliminated, and active and chronic designations of class III and IV were replaced by the activity and chronicity indices that should be applied to all classes. In order to improve the LN classification, further studies will

We thank our professors, the Department of Pathology and the Botucatu

ISN/RPS classification: Class IV-G (A/C)

NIH Activity and Chronicity Indices:

Activity: subendothelial deposits 2+, glomerular hypercellularity 3+, exsudate of neutrophils 2+, necrosis 2+, cellular crescents 2+, interstitial inflammatory infiltrate 3+. Total = 14

Chronicity: glomerular sclerosis 1+, tubular atrophy 1+, interstitial fibrosis 1+. Total =3

#### **Box 1.**

*Biopsy Report Interpretation of Lupus Nephritis*

Biopsy Report

ID: RPS, caucasian, female with 38 years-old

*Lupus Nephritis: Renal Biopsy Guiding the Clinician DOI: http://dx.doi.org/10.5772/intechopen.97169*

indices useful, and the biopsy reports should include routinely, with a detailed description of the types of active and chronic lesions and proportion of glomeruli affected (**Figures 1**–**3** and **Box 1**). Despite these unresolved controversies, active lesions versus chronic lesions, in addition to class of LN, influence response to therapy. The ISN/RPS recently presented a consensus report from a meeting of an international nephropathology working group in 2016. Briefly, they proposed new definitions for mesangial hypercellularity and different patterns of crescents; endocapillary proliferation was replaced by endocapillary hypercellularity, the IV-S and IV-G subclasses were eliminated, and active and chronic designations of class III and IV were replaced by the activity and chronicity indices that should be applied to all classes. In order to improve the LN classification, further studies will be carried out to validate the new proposal [38].
