C5 and chronic kidney disease: The results indicate that in patients with late stage IgAN (stage 4 CKD during renal biopsy), complement terminal pathway was significant activated in kidneys, and local deposits of complement C3a and C5a, as well as high expression of C3aR and C5aR were closely related to baseline renal function and proteinuria levels, and might accelerate the progression of renal function to ESRD.