Basophils are increased and express increased levels of interleukin-4 in the parotid lesions of Kimura disease

BACKGROUND: Kimura disease (KD) is a systemic soft-tissue disease that leads to formation of painless masses in lymph nodes, with the highest predilection for the head and neck and especially the parotid gland. KD lesions are characterized by marked eosinophil infiltration, production of IgE and increased expression of T-helper type 2 (Th2) cytokines (interleukin [IL]-4, IL-5, etc.). Skewing to a Th2 inflammation is also demonstrated in the peripheral blood, with elevated eosinophils and high IgE levels. It is thought that basophils may play important roles in orchestrating this Th2 inflammation via IL-4 production leading to the induction of IgE synthesis as well as eosinophil infiltration. However, there are no reports as yet on the role of basophils in KD. OBJECTIVE: The present study was performed to investigate the potential role of basophils in the pathogenesis of KD. In this context we also examined the expression of IL-4 in basophils in the KD lesions. METHODS: By immunohistochemistry using a monoclonal antibody against a basophil marker ProMBP1 we investigated the number and distribution of basophils in the KD lesions. By double immunohistochemistry we analyzed the colocalization of IL-4 in basophils. RESULTS: There was an increased number of basophils infiltrating the KD parotid gland lesions as compared to that in normal control parotid tissue. By double-immunofluorescence we found that approximately 7% of IL-4-positive cells in KD patients' parotid glands were basophils. CONCLUSION: Basophils may also play a role in the pathogenesis of KD, leading to the induction of IgE synthesis and eosinophil infiltration.