Immunohistochemical study of fibroblasts and mast cells in chronic submandibular sialadenitis

Aim: To further our understanding of the processes involved in fibrosis that occurs in chronic submandibular sialadenitis by investigating the distribution of myofibroblasts, CD34‐positive fibroblasts and tryptase‐containing mast cells. Materials and methods: Thirty specimens of chronic submandibular sialadenitis with varying degrees of fibrosis and five normal submandibular glands were examined immunohistochemically for the presence of CD34, α‐smooth‐muscle‐actin, desmin and tryptase. Results: Myofibroblasts were not demonstrated by the techniques for α‐smooth‐muscle‐actin or desmin. CD34‐positive fibroblasts were found around normal and moderately atrophic acini, but were not found around extremely atrophic acini and duct‐like structures or in periductal and interlobular fibrous tissue. Tryptase‐containing mast cells were found around vessels in normal submandibular glands. They were found in increased numbers in chronic submandibular sialadenitis, particularly in glands with widespread fibrosis, in which they were found in the fibrous tissue, and in which the increase was statistically significant. Conclusions: The results of this investigation suggest that tryptase‐containing mast cells are likely to be involved in the fibrosis of chronic submandibular sialadenitis, but myofibroblasts and CD34‐positive fibroblasts are not.