Type I MPGN is associated with a variety of disorders, including hepatitis, especially hepatitis C, cryoglobulinemia, monoclonal gammopathies, systemic lupus erythematosus, and bacterial endocarditis or other chronic bacterial infections . Idiopathic Type I MPGN is rare. Biopsy samples usually stain for C3 and properdin. However, immunoglobulin G is also present in most cases, especially if the biopsy is performed early in the course of the disease suggesting antibody production as a possible therapeutic target.