Differences between type I and II membranoproliferative glomerulonephritis

Recurrence of immune complex and complement-mediated membranoproliferative glomerulonephritis in kidney transplantation

INTRODUCTION

Membranoproliferative glomerulonephritis (MPGN) represents a histologic pattern of glomerular injury that may be due to several aetiologies. Few studies have comprehensively analysed the recurrence of MPGN according to the current classification system.

METHODS

We collected a multicentre, retrospective cohort of 220 kidney graft recipients with biopsy-proven native kidney disease due to MPGN between 1981 and 2021 in 11 hospitals. Demographic, clinical and histologic parameters of prognostic interest were collected. The main outcomes were time to kidney failure, time to recurrence of MPGN and disease remission after recurrence.

RESULTS

The study group included 34 complement-mediated and 186 immune complex-mediated MPGN. A total of 81 patients (37%) reached kidney failure in a median follow-up of 79 months. The main predictors of this event were the development of rejection episodes and disease recurrence. In all, 54 patients (25%) had a disease recurrence in a median of 16 months after kidney transplantation. The incidence of recurrence was higher in patients with dysproteinaemia (67%) and complement-mediated MPGN (62%). In the multivariable model, complement-mediated MPGN emerged as a predictor of recurrence. A total of 33 patients reached kidney failure after recurrence. The main determinants of no remission were early time to recurrence (<15 months), estimated glomerular filtration rate <30 mL/min/1.73 m2 and serum albumin <3.5 g/dL at the time of recurrence.

CONCLUSIONS

One-fourth of the patients with native kidney disease due to MPGN developed clinical recurrence in the allograft, especially in cases with complement-mediated disease or in those associated with dysproteinaemia. The kidney outcomes of disease recurrence with currently available therapies are heterogeneous and thus more effective and individualized therapies are needed.

Dense deposit disease: new insights

PURPOSE OF REVIEW

Dense deposit disease is a rare but devastating disease primarily affecting children. This review focuses on new information regarding the pathophysiology of dense deposit disease, its appearance histopathologically, its relationship to other diseases including macular degeneration and acquired partial lipodystrophy and potential new therapies.

RECENT FINDINGS

The microscopic features of dense deposit disease have been separated into five patterns with only about 25% of patients showing membranoproliferative features. The subtle interplay between genetic changes in complement regulatory proteins and dysregulation of the alternative pathway of complement is now more evident. Haplotype mapping has shown at-risk phenotypes of complement factor H associated with the development of dense deposit disease. Treatment protocols are empiric and not very effective. New information on complement inhibitors and plasma exchange, however, has brought hope for new therapies in the near future.

SUMMARY

Understanding of the pathology and the pathophysiology of dense deposit disease has advanced rapidly in the last decade. New efforts in genetic mapping along with the development of novel inhibitors of the complement system will lead to improved care for patients afflicted with this uncommon condition.