Cryoglobulins in primary biliary cirrhosis: prevalence and modulation by immunosuppressive therapy

Cryoglobulins were measured in 25 patients with PBC and, for comparison purposes, in 25 age- and sex-matched normal individuals as well as 25 patients with chronic active hepatitis (CAH). Cryoglobulins were present in all patients with PBC (median protein content 18 mg/l, range 8-233) and consisted predominantly of IgM, while none of the normal controls and only 20% of the patients with CAH had cryoglobulins. In PBC, a statistically significant correlation was found between cryoglobulin-IgM concentration and other immunological measurements, such as the serum IgM level (p = 0.003) and Clq binding (p less than 0.001). Cryoglobulin-IgM also correlated significantly with alkaline phosphatase (p = 0.002) and liver fibrosis (p = 0.013), but only in a larger group of patients with PBC. In a longitudinal study of patients with PBC, no changes in the cryoglobulin concentration were found following treatment with D-penicillamine alone or placebo, but the cryoglobulin-IgM level decreased significantly during low-dose combination therapy of D-penicillamine and prednisone (median 15,4 mg/l); this was accompanied by a statistically significant decrease in serum alkaline phosphatase. The relation between cryoglobulin-IgM, serum alkaline phosphatase and liver fibrosis is discussed with regard to the pathogenesis of PBC.