What is the main underlying mechanism of membranoproliferative glomerulonephritis type 2?

Membranoproliferative glomerulonephritis type 2, also known as dense deposit disease, is primarily characterized by the persistent activation of the alternative complement pathway. This condition is associated with the presence of complement component C3 deposits within the renal glomeruli, which leads to inflammation and subsequent glomerular injury. The alternative complement pathway is part of the innate immune system and is typically activated in various immune-mediated processes. In this specific type of glomerulonephritis, the dysregulation and excessive activation of this pathway are central to its pathogenesis, resulting in the unique features observed in renal histology and clinical presentation.

Understanding this pathophysiological mechanism is crucial because it distinguishes type 2 membranoproliferative glomerulonephritis from other forms that may involve primary immune complex deposition, such as in infections or autoimmune diseases. This knowledge is important for guiding the approach to treatment, which may involve targeting the complement system in patients suffering from this specific type of renal disease.