154 of the subjects belonged to the asthma group, and 98, to the normal control group

154 of the subjects belonged to the asthma group, and 98, to the normal control group. measured. We performed pulmonary function assessments and methacholine challenge tests, while measuring total eosinophil count, total serum IgE, and serum ECP in all subjects. == Results == Asthmatic children had significantly higher levels of BAFF in induced sputum [26.50 (10.50-100.27) pg/mL] compared to healthy children [18.32 (7.68-44.63) pg/mL;P=0.011]. Sputum BAFF positively correlated with sputum eosinophils (=0.406,P<0.001) and sputum ECP (=0.789,P<0.001). Significant unfavorable correlations were found between sputum BAFF and FEV1 (=-0.291,P<0.001) or post-bronchodilator AG-L-59687 AG-L-59687 FEV1 (=-0.334,P<0.001), whereas nonsignificant correlations were found between sputum BAFF and bronchial hyperresponsiveness, serum eosinophil count, and serum ECP. == Conclusion == These findings suggest that BAFF may play a role in childhood asthma, and BAFF levels in sputum could be a supportive marker that represents airway inflammation, especially eosinophilic inflammation. Keywords:B cell-activating factor, Child, Asthma, Sputum == Introduction == Asthma is a chronic inflammatory disease in the airway that causes reversible or irreversible contraction of the airway and causes sudden dyspnea through a complex inflammatory reaction that includes allergic reactions. Asthma occurs from the interaction of genetic factors and environmental factors. One of the most important pathophysiologies in asthma, however, is an allergic inflammation that is caused by persistent exposure to allergens1). When an allergen is usually recognized by Th2 cell, cytokines such as IL-4 and IL-5 that promote the maturation and differentiation of the B cell are secreted due to the activation of the Th2 cell. These cytokines induce the B cell to be differentiated into a plasma cell and to produce the immunoglobulin E (IgE) antibody that has an important role in allergic inflammation2). B cell-activating factor (BAFF), also known as BLys, TALL-1, zTNF4, or THANK, is usually part of the tumor necrosis factor family and is known as having an important role in differentiating the B cell and maintaining the shape of a mature B cell. In particular, BAFF is an important factor of the proliferation, differentiation, and survival of an undifferentiated B cell in the AG-L-59687 spleen3-5). A previous study reported that this B cell in the follicular zone and the marginal zone was not found in a BAFF-deficient mouse, which AG-L-59687 indicates that BAFF is an essential factor of the homeostatic expression, differentiation, and proliferation of the B cell6,7). The high concentration of BAFF was clinically measured in patients with autoimmune diseases that show the over-differentiation of the B cell such as in rheumatic arthritis, autoimmune diabetes, Sjgren's syndrome, and LAMA1 antibody multiple sclerosis7,8). The activity of BAFF was also observed in the T cell9), and it was further found that BAFF affects the regulation of the interaction between an antigen-presenting cell and the T cell4). Based on the results of a previous study, several studies have been recently conducted to identify the detailed mechanism in which BAFF has a certain role in the allergic reaction that is a multiple immune response of the T cell and the B cell10-12). They reported that this BAFF concentration in the serum in patients with asthma was higher than in the normal group10), but that there was no difference between the patients with atopic dermatitis and the normal group11). Therefore, the exact role of BAFF in allergic diseases is not yet known. In this study, the level of BAFF in the sputum of patients with asthma, a typical allergic disease, was measured to investigate AG-L-59687 its clinical significance and correlation. In addition, its associations with conventional asthma-related factors and pulmonary function variables were investigated. == Materials and methods == == 1. Subject == Two hundred and fifty-two children who visited Severance children’s hospital were investigated. Of the 252 children, 154 subjects who were diagnosed with asthma were assigned to the patient group, and 98 subjects were assigned to the control group. According to the guidelines of the American Thoracic Society, asthma was defined as the cases of the pediatric patients who visited the hospital within the past 12 months due to cough without cold, wheezing, and dyspnea, in whom bronchial hyperresponsiveness (PC20<16 mg/mL) was observed in a methacholine bronchial.