More importantly, both α3(IV)NC1-specific T cells and natural anti-GBM antibodies were present in the sera of healthy individuals (42, 43), and thus the exposure and expansion of α3(IV)NC1 might contribute to the breakdown of immune tolerance and trigger the autoimmunity leading to the development of anti-GBM disease (44). This evidence concerns the gene COL18A1 and Autoimmunity.