Background and Aims
C3 glomerulopathy (C3G) is a recently defined entity, characterized by the dysregulation of the complement pathway, leading to deposition of C3 complement in the glomeruli, with no immunoglobulins, leading to glomerular inflammation. C3G encompasses 2 disorders: C3 glomerulonephritis (C3GN) and Dense Deposit Disease (DDD), distinguished by their morphological pattern. Although multiple pharmacological treatments exist to control the progression of the disease, for patients reaching End-Stage Kidney Disease, kidney transplantation remains the last resort. While it is known that membranoproliferative glomerulopathies carry a risk of recurrence after transplant, no large-scale meta-analysis was done after 2015 to assess if the precise recurrence risk and remission duration for C3 glomerulopathies.
The goal of this work is to determine if there is currently enough literature specific for C3G to conduct such a meta-analysis.
Method
Our research protocol was guided by the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P), and the Joanna Briggs Institute Critical Appraisal Tools. A search was conducted in PubMed, Web of Science and Scopus databases, using a specific search string, at the conclusion of which, 185 papers were found. The identified papers were subsequently screened by the 2 authors independently using precise inclusion and exclusion criteria. The screening resulted in the final inclusion of 7 papers, on which a qualitative synthesis was performed. The information extracted was organized on basis of demographics, time of transplantation, disease recurrence and disease-free period post-transplantation.
Results
Among the 7 papers selected, 2 were case series and 5 were case reports. In total, 23 patients were reported as having recurrence of C3G. For the patients whose age at diagnosis was known, it ranged between 9 and 51 years of age. Among the 23 patients, 16 of them were male, while 7 of them were females. The C3G subtype was determined for 21 patients, with 7 being classified as having DDD, and 14 having C3GN. The age of transplant was reported for 20 patients, ranging from 11 to 70 years old. The disease-free period between the kidney transplant and the recurrence of the disease ranged from 14 days to 101 months, with 1 case series paper only reported the median time to recurrence in months (14[0-80] for C3GN patients and 15[2-32] for DDD patients). The same paper reported the post-transplant recurrence rate among transplanted patients, determined as 10 to 12 for C3GN patients and 6 to 7 for DDD patients.
Conclusion
While C3G, with its 2 subtypes, have been well defined entities for 5 years, our review reveals that very little research about the post-transplant evolution and recurrence of these disease has been done. While extensive research can be found on the recurrence risks of Membranoproliferative Glomerulonephritis, we believe that with the new classification, more data on the new subtypes is necessary to guide the decision-making of clinicians for these patients.
