Abstract: [Problem] To provide a therapeutic method specialized for an inflammatory disease such as intractable vasculitis and an infectious disease, which is different from the previous therapeutic methods, in which a target molecule was not determined, by determining the target molecule useful for treating these diseases. [Solution] According to one aspect of the present invention, a prophylactic and/or therapeutic agent for an infectious disease or an inflammatory disease which contains an antibody recognizing apolipoprotein A2 (APOA2) as an active ingredient is provided.