Helper T lymphocytes specific for cytokeratin 19 in patients with primary biliary cirrhosis

We demonstrated the expression of cytokeratin 19 (CK19) in biliary cells in chronic non-suppurative destructive cholangitis (CNSDC) and hypothesized t hat this expression may have a correlation with the disease process in addi tion to cellular immunity which is believed to be involved in the pathogene sis of primary biliary cirrhosis (PBC). It is, therefore, important to clar ify whether the destruction of bile ducts and biliary cells are caused by c ellular immunity including helper T lymphocytes (Ths) and cytotoxic T lymph ocytes (CTLs) specific for CK19. We examined the existence of helper T lymp hocytes specific for CK19 in patients with PBC. As a result, the frequencie s of responders having CK19 specific helper T lymphocytes and the stimulati on index (SI) of the proliferative responses of peripheral blood mononuclea r cells (PBMCs) were significantly higher and larger in patients with PBC c ompared with those of patients with chronic hepatitis C and normal subjects . The phenotype of proliferating PBMCs specific for CK19 were predominantly CD4+ Th1 cells. The Th1 response may help the induction of CTLs specific f or CK19, and these CTLs could attack biliary cells. (C) 2001 Elsevier Scien ce B.V. All rights reserved.