The present invention provides compositions and methods useful in the diagnosis and treatment of autoimmunity-related disorders, including cancers and other disorders involving angiogenesis, as well as non-cancer disorders involving a dysfunction in the immune system. In some embodiments, the invention described a plasma assay. In other embodiments, urine assay. In certain other embodiments, the invention provides therapeutic methods comprising removing toxic autoantibodies from the circulation of a patient, e.g., via plasmapheresis, and subsequently infusing the patient with one or more immunoglobulins or immunoglobulin complexes to restore the immune system of the patient to a baseline status whereby the patient's restored immune system either eliminates the source of the disorder {e.g., in the case of cancers) or no longer causes the disease or disorder {e.g., in the case of autoimmune disorders such as multiple sclerosis, psoriasis, latent autoimmune type 1 diabetes in adults (LADA) and the like). Methods of making the high activity IVIG preparation are also provided.
