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Abstract: SA-PO965

Clinical Significance of IgM and C3 Immunofluorescence Deposition Patterns in Patients with Focal Segmental Glomerulosclerosis

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Figueiredo, Gabriel, Universidade de Sao Paulo Hospital das Clinicas, Sao Paulo, São Paulo, Brazil
  • Cecchini, Betina Fincatto, Universidade Nove de Julho, Sao Paulo, SP, Brazil
  • Jorge, Lectícia, Universidade de Sao Paulo Hospital das Clinicas, Sao Paulo, São Paulo, Brazil
  • Yu, Luis, Universidade de Sao Paulo Hospital das Clinicas, Sao Paulo, São Paulo, Brazil
  • Woronik, Viktoria, Universidade de Sao Paulo Hospital das Clinicas, Sao Paulo, São Paulo, Brazil
  • Dias, Cristiane B., Universidade de Sao Paulo Hospital das Clinicas, Sao Paulo, São Paulo, Brazil
Background

The presence of IgM and C3 deposits on immunofluorescence in some patients with Focal Segmental Glomerulosclerosis (FSGS) are considered to be a trapping of these molecules by mesangial sclerosis. However, there are studies that associate these deposits with a worse renal prognosis when compared to patients with negative immunofluorescence or only IgM deposit. We conducted this study aiming to evaluate the association of worse renal outcome with the presence of IgM and C3 deposits in glomeruli of patients from a Brazilian cohort with FSGS.

Methods

This is a retrospective study of clinical, laboratory, light microscopy histopathological and immunofluorescence (IF) data of patients diagnosed with FSGS, in the Nephrology Service of the Hospital das Clínicas of the School of Medicine of USP, from 2009-2017. Through immunofluorescence the patients were divided into four groups: with concomitant IgM + C3 deposition, IgM only, C3 only and without any deposition. These groups were compared to each other regarding data at diagnosis and at the end of follow-up.

Results

In the stipulated period, 114 patients were eligible for the study. The most commonly found IF patterns were concomitant IgM + C3 deposits in 46 patients (40.4%) and no deposits in 43 (37.7%). The other two patterns found were, exclusive IgM or C3 deposition, which occurred in seven (6.1%) and 18 patients (15.8%), respectively. When comparing these four groups, baseline creatinine, final creatinine and final proteinuria were significantly higher in the immunofluorescence groups with IgM + C3 and exclusive C3 deposition. The pattern of Collapsing Glomerulopathy was statistically significantly more frequent in the groups with IgM + C3 and exclusive C3 immunofluorescence (28.2 and 22.2% respectively) compared to those with negative immunofluorescence and exclusive IgM deposition (11.6 and 0% respectively) with p<0.0001. These first two groups also had the highest percentages of end-stage renal disease compared to the last two groups.

Conclusion

Our study showed that the presence of IgM and C3 on immunofluorescence is related to a worse renal prognosis. There is a need to return to the theme of a probable participation of the complement system in this disease.