Mast cell chymase expression in Helicobacter pylori-associated gastritis

Aims: To study the role of mast cell chymase in the inflammatory processes of human chronic gastritis. Experimental studies have shown that mast cell chymase stimulates inflammatory cell accumulation, and contributes to angiotensin II formation. Methods and results: Tissue sections from human stomachs with Helicobacter pylori‐associated gastritis (surgery/autopsy n = 20; biopsy n = 16) and normal stomachs (n = 10) were studied using immunohistochemical single and double labelling techniques. Monoclonal antibodies used were directed against mast cell chymase, tryptase, neutrophils (CD66b, elastase, and myeloperoxidase), macrophages, T‐lymphocytes, and interleukin (IL)‐4. The expression of angiotensin‐converting enzyme and angiotensin II type 1 receptor was investigated using immunohistochemical analysis and the reverse transcription‐polymerase chain reaction. The number of chymase‐positive mast cells was significantly higher (P