Hepatic chymase level in chronic hepatitis: co-localization of chymase with fibrosis.

Chymase, secreted by mast cells, is associated with angiotensin II production and fibrosis of myocardium and renal interstitium. Assuming that chymase also is involved in liver fibrosis, we previously established an enzyme-linked immunosorbent assay for chymase in human liver tissue. In the present study, we explored the localization of mast cells in the liver using antibodies against human chymase and also studied relationships between hepatic chymase level and histologic findings in 49 patients with chronic hepatitis. By the international classification, fibrosis was staged from F0 to F4 and activity was graded from A1 to A3. Cells immunoreactive for chymase were seen throughout portal areas and intralobular sinusoidal walls, largely colocalizing with inflammation and fibrosis. Hepatic chymase levels in F3 and F4 cases were greater than in F1 and F2 (F3+F4, 30.8+/-41.2 ng/mg vs. F1+F2, 5.7+/-6.6 ng/mg; P<0.01). Chymase in A3 casese (39.4+/-50.8 ng/mg) was more abundant than in A1 (3.7+/-4.3 ng/mg) or A2 (12.8+/-19.4 ng/mg); P<0.05 for each. Our findings suggest that hepatic chymase level is implicated in fibrosis and activity in human liver disease.