INCREASED EXPRESSION OF PROLIFERATING CELL NUCLEAR ANTIGEN IN AUTOIMMUNE HEPATITIS IN A PATIENT WITH RAISED SERUM CONCENTRATION OF CA19-9

A 52 year old woman had autoimmune hepatitis and an increased concentr ation of serum carbohydrate antigen 19-9 (CA19-9). The origin of the r aised CA19-9 was studied using immunohistochemistry. Liver biopsy sect ion showed chronic active hepatitis with large numbers of proliferated bile ductules. Immunohistochemical analysis revealed that the prolife rated bile ductule cells were positive for proliferating cell nuclear antigen (PCNA) and for CA19-9. It is speculated that the raised serum CA19-9 concentration was derived from proliferated bile ductule cells and these cells, which are positive for PCNA, may be able to produce h igh concentrations of CA19-9.