Clinical Significance Of Expression Of Tryptase And Chymase In Normal Scalps And Lesions Of Alopecia Areata

BackgroundAlopecia areata (AA) is a benign, non-scarring disease. People of any age can be affected with it, and there isn’t much difference between the incidence of male and female. About5percent of AA patients can develop into AT (complete baldness of the scalp) gradually or rapidly; and few of them into AU, as their hair loss involves the scalp, eyelashes, beard, pubis, hircus, and even all wolly hairs.The pathogeny of AA isn’t clear now. Heredity、environment and psychic factors may be related to it. According to studies of recent years, AA is an immune response-related, hair-damaged inflammatory disease, as inflammatory cells and cytokines in the lesions play important roles in the pathogenesis.Mast cells (MC) widely distribute in connective tissue, mucosal tissue and perivascular, and, there are many bioactivators in it. So, MC is not only an immune effector cell in immediate allergy, but also play a part in the pathologic process of many diseases. Tryptase and chymase are the usual markers of MC.Scholars pay more attention to the relationship of MC with the pathogenesis, development and prognosis of diseases in recent years, But few studies were committed to the relationship between MC and AA.ObjectiveTo investigate the expression of tryptase and chymase in normal scalps, and their relationship with activity, severity and course of AA.Methods The skin specimen of AA lesions and normal scalp were taken, and paraffin sections were used for immunohistochemical examination to determine the expression and distribution of tryptase and chymase.ResultsTryptase could be found in perifollicular, the sebaceous glands and perivascular regions. Only few chymase positive MC could be seen in normal tissues, and a small number in AA lesions, and chymase mainly distribute around the hair follicles.The expression of tryptase was higher in AA patients than that of the controls and predominated in the active phase and extensive form(P<0.05), while there was no significant difference between the course of the disease longer than one year and shorter than one year. However, the expression of chymase in the controls and AA patients had no statistical significance(P>0.05).ConclusionThe distribution of MC, especially tryptase positive MC in normal scalps can make for it’s interaction with nerves and blood vessels, and the defense of pathogen and allergens.MC with the positive expression of tryptase may be correlated with the behavior of AA, and may be of value to predict the prognosis of AA.