Auto Anti-N—An Additional Example

This report is about an 85-year-old man with carcinoma of the urinary bladder who was type MN and had an antibody with N specificity. Absorption and elution studies proved this example of anti-N to be an autoantibody. Its optimal reactivity at low temperature and 2-mercaptoethanol reduction indicated antibody activity to be associated with an IgM globulin. The antibody failed to react with ficin treated cells. Both direct and indirect antiglobulin tests were negative. There was no clinical evidence of immune hemolysis in this patient. The serologic characteristics of the antibody were constant from discovery until the patient's death due to metastatic neoplasm ten weeks later.