Forbindelse, som bindes til leukocytter, og lægemiddel indeholdende forbindelsen i mærket tilstand som den aktive bestanddel

A compound binding to leukocytes, which comprises Met-Leu-Phe or Nle-Leu-Phe serving as the leukocyte-binding site of a formyl peptide receptor (FPR), a binding part comprising Ser or Thr elevating the binding ratios to monocytes and lymphocytes in all leukocytes, a group which can be labeled with a radioactive metal or a paramagnetic metal, and a spacer binding them shows binding properties specific to all leukocytes, i.e., neutrophils, monocytes and lymphocytes both in vivo and in vitro and can be labeled with a radioactive metal or a paramagnetic metal. Owing to these characteristics, this compound is highly useful in SPECT image diagnosis, PET image diagnosis, MRI image diagnosis and so on wherein imaging is performed in a site with vigorous leukocyte infiltration accompanied by an immune reaction in an individual.