HUMAN COMBINATORIAL AUTOANTIBODIES AND MOUSE MONOCLONAL-ANTIBODIES TOPDC-E2 PRODUCE ABNORMAL APICAL STAINING OF SALIVARY-GLANDS IN PATIENTS WITH COEXISTENT PRIMARY BILIARY-CIRRHOSIS AND SJOGRENS-SYNDROME

An increase in the incidence of Sjogren's syndrome in patients with pr imary biliary cirrhosis has been noted. Indeed, primary biliary cirrho sis has been described as a ductal disease with involvement not only o f the biliary tract but of epithelial ductal cells in other organs. We have previously reported the development of a panel of mouse monoclon al antibodies directed at PDC-E2, the major autoantigen of primary bil iary cirrhosis. One such antibody, C355.1, but none of the other monoc lonal antibodies, reacted not only with mitochondria but also with the apical region of biliary epithelium of patients with primary biliary cirrhosis but not in similar specimens from patients with other liver disease or normal human liver. In addition, we have reported the devel opment of human combinatorial antibodies specific for PDC-E2; these re agents also reacted uniquely with the biliary epithelium of patients w ith primary biliary cirrhosis. In this paper, we have performed a simi lar study and have compared the staining of monoclonal antibody C355.1 and a human combinatorial antibody, SP4, with control monoclonal anti bodies with respect to their reactivity of salivary glands in 9 patien ts with primary biliary cirrhosis associated with Sjogren's syndrome, 11 patients with Sjogren's syndrome alone and 7 control patients. Inte restingly, the apical region of the salivary gland epithelial cells of approximately 50% of patients with coexisting primary biliary cirrhos is and Sjogren's syndrome had a staining pattern similar to that seen in primary biliary cirrhosis biliary epithelium. In contrast, we did n ot observe this reactivity in any patient with Sjogren's syndrome alon e or in any control patient. These data suggest that similar mechanism s may explain the abnormal expression pattern of PDC-E2 or a cross-rea cting molecule in the ductal tissue of patients with primary biliary c irrhosis.