Ueda Yutaka, Nakagome Kazuyuki, Katayama Kazuki, Iemura Hidetoshi, Miyauchi Sachiko, Noguchi Toru, Kobayashi Takehito, Soma Tomoyuki, Itazawa Toshiko, Nagata Makoto
Department of Respiratory Medicine, Saitama Medical University, Saitama, Japan.
Department of Pediatrics, Saitama Medical University, Saitama, Japan.
Asia Pac Allergy. 2024 Dec;14(4):183-190. doi: 10.5415/apallergy.0000000000000157. Epub 2024 Aug 16.
Eosinophil inflammation often persists in the airways of severe asthmatics, even under treatment with high-dose inhaled corticosteroids. Biologics for various type 2 cytokines have been recently developed for corticosteroid-resistant, eosinophil-dominant, severe asthma. However, it is unclear whether these biologics act directly on eosinophils.
In this study, we examined whether various type 2 cytokines targeted by biologics can directly modify the functions of eosinophils obtained from the peripheral blood of healthy individuals.
Peripheral eosinophils of healthy subjects were purified by conventional negative-depletion methods using anti-CD16 beads to avoid the priming effect (i.e., stimulation ) to the maximum extent possible. Eosinophils were stimulated with interleukin (IL)-4, IL-5, IL-13, or thymic stromal lymphopoietin (TSLP), and eosinophil adhesiveness to recombinant human-intercellular adhesion molecule (ICAM)-1 was evaluated by eosinophil peroxidase assays. The effect of these cytokines on eosinophil superoxide anion (O ) generation was evaluated by the superoxide dismutase-inhibitable reduction of cytochrome C. To determine whether eosinophil degranulation was induced, the concentration of eosinophil-derived neurotoxin (EDN) in the supernatant was measured using enzyme-linked immuno sorbent assay.
As reported previously, at 100 pM, IL-5 increased eosinophil adhesiveness to ICAM-1, O generation, and EDN release. Conversely, at concentrations up to 10 nM, IL-4, IL-13, and TSLP did not induce eosinophil adhesiveness, O generation, or EDN release.
Type 2 cytokines other than IL-5 do not directly affect the functions of eosinophils from healthy individuals when used at clinical concentrations. These findings suggest that eosinophils play little, or no, direct role in the effects of anti-IL-4 receptor α or anti-TSLP antibody on severe asthma.
即使在高剂量吸入糖皮质激素治疗下，重度哮喘患者气道中的嗜酸性粒细胞炎症通常仍会持续存在。针对各种2型细胞因子的生物制剂最近已被开发用于治疗糖皮质激素抵抗、以嗜酸性粒细胞为主的重度哮喘。然而，尚不清楚这些生物制剂是否直接作用于嗜酸性粒细胞。
在本研究中，我们检测了生物制剂所靶向的各种2型细胞因子是否能直接改变从健康个体外周血中获取的嗜酸性粒细胞的功能。
采用抗CD16磁珠通过传统阴性去除法纯化健康受试者的外周嗜酸性粒细胞，以最大程度避免启动效应（即刺激）。用白细胞介素（IL）-4、IL-5、IL-13或胸腺基质淋巴细胞生成素（TSLP）刺激嗜酸性粒细胞，通过嗜酸性粒细胞过氧化物酶测定评估嗜酸性粒细胞对重组人细胞间黏附分子（ICAM）-1的黏附性。通过超氧化物歧化酶抑制的细胞色素C还原评估这些细胞因子对嗜酸性粒细胞超氧阴离子（O）生成的影响。为确定是否诱导了嗜酸性粒细胞脱颗粒，使用酶联免疫吸附测定法测量上清液中嗜酸性粒细胞衍生神经毒素（EDN）的浓度。
如先前报道，在100 pM时，IL-5增加了嗜酸性粒细胞对ICAM-1的黏附性、O生成和EDN释放。相反，在高达10 nM的浓度下，IL-4、IL-13和TSLP未诱导嗜酸性粒细胞黏附、O生成或EDN释放。
临床浓度使用时，除IL-5外的2型细胞因子不会直接影响健康个体嗜酸性粒细胞的功能。这些发现表明，嗜酸性粒细胞在抗IL-4受体α或抗TSLP抗体对重度哮喘的作用中几乎不发挥直接作用，或根本不发挥直接作用。
