Type III cryoglobulinemia (15-30% of cases) involves circulating polyclonal IgM protein with rheumatoid factor activity bound to polyclonal IgG and blood complement components; autoimmune diseases and, less commonly, hepatitis virus C infection or lymphoproliferative disorders are the cause of this type of croglobulinemia. Only types I and II are defined as plasma cell dyscrasias.Patients suffering type 1 cryoglobulinemia present with symptoms due to cold temperature-induce blood hyperviscosity and consequential interruptions of blood flow, e.g. skin lesions (lower extremity purpuric spots and papules, acrocyanosis, necrosis skin ulcers, livedo reticularis urticaria), peripheral neuropathy, blurred vision, loss of vision, hearing loss, headaches, confusion, transient ischemic attacks, chest pain, heart failure, glomerulonephritis, kidney failure, oral bleeding, and nasal bleeding. Rarely, patients may present with catastrophic decreases in blood flow to vital tissues and require emergency treatment. Symptomatic patients typically exhibit levels of a myeloma protein >5 gram/liter and can be diagnosed by simple observing the temperature-induced, reversible induction of serum precipitate formation. Patients, particularly those with catastrophic presentations, are treated with plasma exchange and/or plasmapharesis to reduce the load of circulating myeloma proteins and relieve acute symptoms. Patients with an overt malignancy are treated with the chemotherapy regimens used for Waldenstroms macroglobulinemia or multiply myeloma; patients with MGUS precursors to these diseases appear less responsive to these chemotherapeutic regimens.
Plasma cell dyscrasias (also termed plasma cell disorders and plasma cell proliferative diseases) are a spectrum of progressively more severe monoclonal gammopathies in which a clone or multiple clones of pre-malignant or malignant plasma cells (sometimes in association with lymphoplasmacytoid cells or B lymphocytes) over-produce and secrete into the blood stream a myeloma protein, i.e. an abnormal monoclonal antibody or portion thereof. The exception to this rule is the disorder termed non-secretory multiple myeloma; this disorder is a form of plasma cell dyscrasia in which no myeloma protein is detected in serum or urine (at least as determined by conventional laboratory methods) of individuals who have clear evidence of an increase in clonal bone marrow plasma cells and/or evidence of clonal plasma cell-mediated tissue injury (e.g. plasmacytoma tumors). Here, a clone of plasma cells refers to group of plasma cells that are abnormal in that they have an identical genetic identity and therefore are descendants of a single genetically distinct ancestor cell. At one end of this spectrum of hematological disorders, detection of one of these myeloma proteins in an individuals blood or urine is due to a common and clinically silent disorder termed MGUS, i.e. monoclonal gammopathy of undetermined significance. At the other end of this spectrum, detection of the myeloid protein is due to a hematological malignancy, i.e.