MYOFIBROBLAST-LIKE CELLS PRODUCE MESSENGER-RNA FOR TYPE-I AND TYPE-III PROCOLLAGENS IN CHRONIC ACTIVE HEPATITIS

In chronic active hepatitis the rate of collagen biosynthesis is large ly determined by intracellular mRNA concentrations. To localize procol lagen mRNA-producing cells, we investigated biopsy specimens from five patients with hepatitis B surface antigen-positive chronic active hep atitis and five patients without liver.disease by in situ hybridizatio n. We used type I and III procollagen cDNAs for transcription to (S-35 )-labeled probes. Parallel sections were stained with anti-actin monoc lonal antibodies. Our results show that cells in which collagen synthe sis is ostensibly enhanced can be localized by in situ hybridization o f procollagen mRNAs. These cells were also anti-actin-positive in para llel sections and were localized in areas of inflammatory cell infiltr ation and necrosis. We conclude that myofibroblast-like cells may expr ess procollagen mRNAs in chronic active hepatitis. Moreover, in situ h ybridization may be a valuable diagnostic tool for providing additiona l morphologic information on the degree of fibrogenesis activity.