{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"The complement component 1q (C1q) is a protein complex involved in the complement system, a part of the innate immune system. C1q together with C1r and C1s form the C1 complex. Antibodies of the adaptive immune system can bind antigen, forming an antigen-antibody complex. C1q binds antigen-antibody complexes, which activates the C1 complexes and initiates the classical complement pathway of the complement system. According to literature, C1q nephropathy is a rare glomerular disease with characteristic mesangial C1q deposition noted on IHC or IF microscopy. Lupus nephritis is an inflammation of the kidneys caused by systemic lupus erythematosus. Immunofluorescence also reveals positively for IgG, IgA, IgM, C3, and C1q."}]}]}