Analysis of serum from a patient with cutaneous leukocytoclastic vasculitis showed a mixed cryoglobulin with a monoclonal IgM kappa-antiglobulin component (6.5 mg/ml), strong rheumatoid factor activity (latex titre 1/5000), and positive serological tests for syphilis (fluorescent treponemal antibody-absorbed and Treponema pallidum haemagglutination assay). After removal of antiglobulin activity...

Cryoglobulinemic vasculitis is a small vessel vasculitis that has been associated with chronic infections and autoimmune, lymphoproliferative, and neoplastic disorders. When no significant etiological factors are identified, it is called essential mixed cryoglobulinemia. A detailed and thorough laboratory investigation is required to exclude all possible causes of cryoglobulin formation. Althou...

We present a case of type 1 cryoglobulinemia with an underlying hematological malignancy. Unusually, the entire unifying diagnosis was made on the basis of the renal biopsy. Initially, serum cryoglobulin was not identified; repeat samples were positive. It is important to note that there is a significant false-negative rate with laboratory testing for cryoglobulin, due, at least in part, to the...

A 70 year old man is described in whom the presence of a cryoglobulin caused a number of unusual laboratory features which were not recognized as being due to a cryoglobulin initially. Pseudoleucocytosis has been recognized in the past. However, the intracytoplasmic inclusion bodies have only rarely been described. The curious appearance of the ESR has not previously been described.

Autoantibodies of the cryoprecipitating IgG3 isotype have been shown to play a significant role in the development of murine lupus-like autoimmune syndrome. At present, the structural basis of IgG3 cryoprecipitation and its role in autoantibody pathogenicity remain to be defined. Using molecular variants of an IgG3 monoclonal rheumatoid factor, 6-19, derived from an autoimmune MRL-Fas(lpr) mous...

Three new cases of cryoglobulinaemia are described, and in each case the presence of the cryoglobulin appeared to be unrelated to the clinical manifestations. Although when examined by paper electrophoresis the abnormal proteins behaved uniformly as normal gamma globulins, marked differences in nature were revealed when ultracentrifugal and immunological analyses were made. One patient had an a...