PROBLEM TO BE SOLVED: To provide a therapeutic agent for diseases caused by neutrophil activation, the therapeutic agent containing a neutrophil activation regulatory agent which has a neutrophil activation controlling function and a neutrophil activation regulating function; and also to provide an inspection method for diseases caused by neutrophil activation.SOLUTION: The invention provides a therapeutic agent for inflammatory diseases associated with neutrophil activation the therapeutic agent using a neutrophil activation regulatory agent containing a histidine rich glycoprotein (HRG) as an active ingredient, and a neutrophil-endothelial cell interaction inhibitor containing the HRG as an active ingredient; and an inspection method for inflammatory diseases associated with neutrophil activation by measuring the amount of HRG in blood.SELECTED DRAWING: Figure 13【課題】好中球活性化の制御機能を有し、好中球活性化調節する機能を有する、好中球活性化調節剤を含む好中球活性化に起因する疾患の治療薬、更に好中球活性化に起因する疾患の検査方法の提供。【解決手段】ヒスチジンリッチ糖タンパク質(HRG)を有効成分とする好中球活性化調節剤、及び該HRGを有効成分とする好中球‐血管内皮細胞相互作用抑制剤とする好中球活性化に伴う炎症疾患の治療薬。更に、血中HRG量を測定することによる好中球活性化を伴う炎症性疾患の検査方法。【選択図】図13