Relationship between systemic autoimmune disease and Mixed cryoglobulinemia
Autoimmune disorders are the second most commonly associated diagnoses with MC (usually type III) after hepatitis C. Sjögren’s syndrome is the most common, followed by systemic lupus erythematosus and rheumatoid arthritis.
Cryoglobulins may be seen in up to 15% to 20% of such patients, but associated vasculitis is seen in only a small fraction. Levels of circulating cryoglobulins are typically much lower than those seen in patients with HCV.
The presence of cryoglobulins correlates with higher disease activity (elevated ESSDAI scores) and is associated with extra-glandular manifestations, lymphoma, and mortality in Sjögren’s syndrome. Cutaneous vasculitis, peripheral neuropathy, elevated RF, and low complement level can be associated with cryoglobulins. Less frequently, cryoglobulins can be found with multiple other rheumatologic and autoimmune disorders, such as antiphospholipid antibody syndrome, Behçet’s disease, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides, and inflammatory bowel disease.
