Abstract: SA-PO265

Triggering Factors and Associated Conditions in C3 Glomerulopathy

Session Information

Category: Glomerular

  • 1005 Clinical Glomerular Disorders

Authors

  • Ravindran, Aishwarya, Mayo Clinic, Rochester, Minnesota, United States
  • Fervenza, Fernando C., Mayo Clinic, Rochester, Minnesota, United States
  • Sethi, Sanjeev, Mayo Clinic, Rochester, Minnesota, United States
Background

C3 glomerulopathy (C3G), comprising C3 glomerulonephritis (C3GN) and dense deposit disease (DDD), is characterized by glomerular accumulation of complement proteins due to over activation of the alternative pathway of complement. Most of the reports on C3G are based on individual cases or small series of C3GN/DDD patients. There are no large scale studies describing the triggers/acquired conditions associated with C3G.

Methods

We identified 114 patients seen at the Mayo Clinic from 2007-2016 with a diagnosis of C3G, of which 102 (89.5%) had C3GN and 12 (10.5%) had DDD.

Results

Our study revealed 3 main triggers/acquired conditions associated with C3G: monoclonal Ig, infections and autoimmune diseases (figure 1). 1) Ninety five (83.3%) of the 114 patients were evaluated for a monoclonal Ig. Overall, 36 (37.9%) had a monoclonal Ig; furthermore 28 (65.1%) patient’s ≥ 50 years had a monoclonal Ig. Twenty-six patients were classified as MGUS/MGRS, 5 as multiple myeloma, 2 as smoldering myeloma, 1 as CLL, 2 with cryoglobulins of which one was associated with lymphoma of the stomach. 2) Thirty-three (28.9%) patients had a history of infection at the time of diagnosis, with upper respiratory tract infection as the most common infection associated with C3G. Post-infectious GN was ruled out as these patients continued to have persistent hematuria long after resolution of the infection. 3). Twenty-seven (23.7%) patients had history of autoimmune diseases. The most common findings of autoimmunity was a positive ANA in 12 (12.2%), positive dsDNA in 6 (8.2%) and positive antiphospholipid antibody in 3 (4.1%) patients.

Conclusion

Triggering factors and acquired conditions are commonly present and can be the principal drivers of C3G. Each case should be evaluated for these conditions as these disorders can be important therapeutic targets in the management of C3G.