Human chemokine Alpha-3 polypeptides and DNA (RNA) encoding such chemotactic cytokines and a procedure for producing such polypeptides by recombinant techniques is disclosed. Also disclosed are methods for utilizing such chemotactic cytokines for the treatment of leukemia, tumors, chronic infections, auto-immune disease, fibrotic disorders, sepsis, wound healing and psoriasis and to stimulate stem cell mobilization. Antagonists against such chemotactic cytokines and their use as a therapeutic to treat rheumatoid arthritis, auto-immune and chronic and acute inflammatory and infective diseases, allergic reactions, prostaglandin-independent fever, ARDS and bone marrow failure are also disclosed. Also disclosed are diagnostic assays for detecting diseases related to mutations in the nucleic acid sequences and altered concentrations of the polypeptides. Also disclosed are diagnostic assays for detecting mutations in the polynucleotides encoding the chemotactic cytokines and for detecting altered levels of the polypeptide in a host.