A family is described in which multiple members are afflicted with liver disease and primary biliary cirrhosis (PBC). In the third generation, one member died of PBC, and a second individual has both symptomatic PBC and selective immunoglobulin A (IgA) deficiency, an association not previously reported. By culturing this patient's lymphocytes in vitro it was shown that the IgA deficiency was due to a failure of B cells to secrete IgA. Two other siblings of this patient have multiple serum biochemical and serologic abnormalities that are sometimes associated with PBC, but they do not have histopathologically overt PBC or IgA deficiency. All three surviving family members have a diminished autologous mixed lymphocyte reaction, an immunologic abnormality that has previously been found in patients with PBC, selective IgA deficiency, and several autoimmune diseases. As there is an association between selective IgA deficiency and certain autoimmune diseases, it is possible that this immunodeficiency contributed to the development of PBC in the patient in whom the two diseases coexisted. Furthermore, the occurrence of PBC in a patient with selective IgA deficiency indicates that the pathogenesis of PBC does not require IgA-dependent immune mechanisms.
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