Kidney Week

Abstract: SA-PO1114

Macrophages as a Marker for Endocapillary Hypercellularity in Lupus Nephritis

Session Information

• Pathology and Lab Medicine: Clinical
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

• 1502 Pathology and Lab Medicine: Clinical

Authors

• Bos, Elisabeth Marika Josephine, Pathan, Rotterdam, Netherlands

Elisabeth Marika Josephine Bos,

• Wilhelmus, Suzanne, Pathan, Rotterdam, Netherlands

Suzanne Wilhelmus,

• Wolterbeek, Ron, Leiden University Medical Centre, Leiden, Netherlands

Ron Wolterbeek,

• Jordan, Natasha, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom

Natasha Jordan,

• D'Cruz, David, Guy's and St. Thomas' Hospitals NHS Foundation Trust, London, United Kingdom

David D'Cruz,

• Isenberg, David, University College London, London, United Kingdom

David Isenberg,

• Cook, H. Terence, Imperial College of London, London, United Kingdom

H. Terence Cook,

• Bruijn, Jan A., Leiden University Medical Center, Dept.Pathology, Leiden, Netherlands

Jan A. Bruijn,

• Bajema, Ingeborg M., Leiden University Medical Centre, Leiden, Netherlands

Ingeborg M. Bajema,

Background

Lupus Nephritis (LN) is a manifestation of Systemic Lupus Erythematosus (SLE) which occurs in up to 60% of patients suffering from SLE. LN is strongly related to mortality and morbidity in SLE, especially class III and IV LN. The interobserver agreement of endocapillary hypercellularity which determines whether a biopsy is classified as class III or IV in LN, has been found to be moderate. In IgAN, the presence of glomerular macrophages was put forward as a surrogate marker for endocapillary hypercellularity. We investigated whether in LN, the presence of glomerular macrophages could serve as a surrogate marker for endocapillary hypercellularity as well.

Methods

99 lupus nephritis biopsies were scored for the number of endo- and extracapillary macrophages per glomerulus using CD68 staining, as well as the overall presence of endocapillary hypercellularity (categorical variable E0/E1) and percentage of glomeruli with endocapillary hypercellularity (continuous variable E-continuous) per biopsy using a silver staining. Overall presence of endocapillary hypercellularity and percentage of glomeruli with endocapillary hypercellularity were both correlated with endo- and extracapillary macrophage count using a Mann-Whitney U test and a Spearman correlation test.

Results

A strong correlation was found between the quantity of glomerular macrophages and the presence of hypercelullarity, as well as between the percentage of glomeruli with endocapillary hypercellularity and number of glomerular macrophages. The correlation was stronger using only endocapillary macrophages in our analysis compared to extracapillary macrophages.

Conclusion

In lupus nephritis, the presence of glomerular macrophages is an excellent surrogate marker for endocapillary hypercellularity. This marker could be a useful tool towards a more effective and reproducible usage of the LN classification.