007 - Cryoglobulins: from science to laboratory practice
Autor(s): I. Brusca, M. Ruggeri, F. Bottan, B. Milanesi, L. Cinquanta, M. Tani, S. Mangraviti, C. Ottomano, M. Gallina per il Gruppo di Studio-Proteine della SIMeL
Issue: RIMeL - IJLaM, Vol. 6, N. 1, 2010 (MAF Servizi srl ed.)
Page(s): 7-12
Summary
Cryoglobulins (CGs) are made up of a mixture ofimmunoglobulins and complements which typically
precipitate at temperatures below normal body temperature (37 °C), and dissolve again if blood is heated. Cryoglobulinemia is often used to refer to a systemic inflammatory syndrome generally involving small-to-medium-vessel vasculitis. Three types of cryoglobulins are recognized, based on whether cryoglobulin is monoclonal and has rheumatoid factor (RF) activity. Type I is a no-RF active monoclonal antibody associated with lymphoma, Waldenström’s macroglobulinemia, and multiple myeloma. Both types II and III are called mixed cryoglobulins and are characterized by the presence of RF antibodies which are monoclonal in type II and polyclonal in type III. Type II is associated with lymphoproliferative diseases; both type I and II can occurin patients with rheumatic diseases and chronic infections. C-Hepatitis-C virus (HCV) is responsible for a large number of cases previously termed as “essential” and not related to lymphoproliferative disorders or autoimmune diseases. A preanalytical phase is essential to correctly detect CG, as blood samples must be kept constantly warmed. The serum is refrigerated for seven days to allow the precipitate to form, then centrifuged and measured to detect the percentage of precipitate. In order to be reported as a cryoglobulin, the precipitate must at least partially redissolve by heating. Immunofixation allows the typing of precipitated immunoglobulins.
Key-words: HCV, mixed cryoglobulinemia, immune complexes, immunoglobulins, rheumatoid factor.