Circulating secretory immunoglobulins of the A and M isotypes in chronic liver disease

Serum levels of secretory IgA (SIgA) and secretory IgM (SIgM) were quantified by an enzyme-linked immunosorbent assay in 97 patients with various chronic liver diseases and 17 patients with uncomplicated ulcerative colitis. The values obtained were compared with 89 matched controls and related to other serum variables. All types of liver disease had elevated median levels of serum SIg. Patients with primary biliary cirrhosis (PBC) had the highest SIg levels, particularly SIgM, but increased total serum IgM was slightly more specific for PBC. Thus, the SIg levels did not add more discriminative information than several other variables. Elevated levels of circulating SIgA correlated mainly with variables that indicate reduced liver function. The difference observed between patients with PBC and primary sclerosing cholangitis (PSC) in the alkaline phosphatase (ALP)-to-SIg ratio is discussed.