The present application provides a drug containing an antibody binding to phospholipase D4 (pld4) and a method for detecting and inhibiting activated B cells using the drug. The application also aims at the treatment of autoimmune diseases and allergic diseases derived from the active ￣ repressor function. In order to solve these problems, the present application provides a monoclonal antibody that binds to the extracellular domain of phospholipase D4 (pld4) protein, or a fragment containing an antigen binding region thereof, as an active ingredient.本申請提供藥物包含與磷脂酶D4(PLD4)結合的抗體以及使用所述藥物檢測及抑制活化的B細胞的方法。本申請還針對來自活性‑阻遏功能的自身免疫疾病及變應病的治療。為了解決這些問題，本申請提供與磷脂酶D4(PLD4)蛋白的細胞外結構域結合的單克隆抗體，或其含有抗原‑結合區的片段作為活性成分。
