[Cryoglobulins in systemic and rheumatological diseases. Report of 70 cases (author's transl)].

Cryoglobulins are immunoglobulins characterized by precipitating when serum is cooled and redissolving when serum is heated. There is strong evidence to consider mixed cryoglobulins as circulating immunocomplexes. Cryoglobulins have been demonstrated in association to hematologic, hepatic, lymphoproliferative, autoimmune and infectious conditions. There is also an essential or idiopathic variant. The present report studies a series of 70 patients with several rheumatic and systemic diseases, and a group of ten patients with cutaneous vasculitis. Significant levels of cryoglobulins have been detected in nine cases (overall incidence 12.8 percent). The diagnoses corresponding to these patients were as follows: systemic lupus erythematosus in three cases, dermatopolymyositis in three cases, Sjögren's syndrome in two cases, and Wegener's granulomatosis in one case. Cryoglobulins could not be demonstrated in patients with rheumatoid artritis, sclerodermia, periarteritis nodosa, cutaneous vasculitis, Reiter's syndrome, ankylosing spondilitis and acute articular rheumatism. Among patients with systemic lupus erythematosus a good correlation has been observed between the presence of serum cryoglobulins, the activity and severity of the diseases and the decrease of serum complement levels.