Expression of Syk is associated with nasal polyp in patients with allergic rhinitis.
Numerous signalings are involved in allergic inflammation. The non-receptor protein tyrosine kinase, Syk, is widely expressed in immune-potentiated cells and plays critical roles in initiating signal transduction in response to the activation of cytokine, chemokine and other types of receptors. It has been hypothesized that Syk expression in allergic nasal mucosa and polyps with allergy is different from non-allergic mucosa, and that changes in Syk expression contribute to the activation of allergic reactions. We examined whether the expression of Syk is found in allergic nasal mucosa and polyps. We investigated the expression of Syk in 46 nasal mucosa and polyps (14 samples from patients with allergic rhinitis and 32 samples with non-allergic chronic sinusitis) using an immunohistochemical technique. Allergic polyps had more Syk positive cells than non-allergic polyps. Syk positive cells were determined to mainly be eosinophils. There was no difference in Syk expression in the lamina propria and nasal gland between allergic mucosa and non-allergic mucosa. Eosinophils in allergic polyps receive an intracellular signal, although the signal is not able to determine the function in the present state. Syk appears to be a promising target molecule for anti-allergic inflammation in allergic rhinitis.