Cryoglobulinemia

Definition (Arth Rtevm 1999:42:2507)

• Proteins that precipitate on exposure to the cold, characterized by their composition

• Type 1 (monoclonal): monoclonal Ig (usually IgM or IgG)

• Type 2 (mixed): monoclonal IgM usu. with RF activity • polyclonal IgG

• Type 3 (polyclonal): polyclonal immunoglobulins Epidemiology

• Female predominance

• Age of onset-50 y Etiologies

• Lymphoproliferative disorders: multiple myeloma.Waldenstrom's macroglobulinemia.

CLU B-cell NHL Usually associated with Type 1 cryoglobulinemia.

• HCV infection: >80% of Pts with Type 2 cryoglobulinemia are HCV RNA © (NE/m

1992:327:1490)

• Autoimmune syndromes: usually associated with Type 3 cryoglobulinemia

• Infections: viral (EBV. CMV), bacterial (endocarditis), and parasitic infections

• Essential (idiopathic)

• Renal transplant recipients, w/ or w/o HCV infection Pathophysiology

• Chronic immune stimulation and/or lymphoproliferation — immune complex (IC) formation

• Defective/insufficient IC clearance -»IC deposition with complement activation

• Promotes: platelet aggregation — small vessel thromboses, inflammation -» vasculitis Clinical manifestations

• General: weakness, low-grade fever

• Dermatologic: lower extremity purpura, livedo reticularis, leg ulcers. Raynaud's phenomenon, leukocytodastic vasculitis

• Rheumatologic: symmetric, migratory arthralgias of small or medium joints

• Renal (50%): glomerulonephritis (proteinuria, hematuria.ARF. hypertension, edema)

• Hematologic: anemia, thrombocytopenia

• Gl: abdominal pain, hepatosplenomegaly. abnormal LFTs

• Neurologic: peripheral neuropathy and mononeuritis multiplex Diagnostic studies

• © cryocrit (amount not necessarily associated with disease activity).

cryoglobulin electrophoresis

• If blood sample not kept at 37° C cryoprecipitation -»loss of RF and li complement

• In Type 2 cryoglobulinemia: © HCV RNA. © anti-HCV Ab

• Biopsy of affected area (skin, kidney) Treatment

• Treat underlying disorder:

chemotherapy and/or radiation for lymphoproliferative disorders antiviral therapy and/or rituximab for HCV {toem 2006:4S:8427) DMARDs for rheumatic disease

• NSAIDs for control of mild symptoms

• Prednisone • other immunosuppressants (eg. cyclophosphamide) for major organ involvement

• Plasmapheresis in severe disease

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