Peptides are provided consisting of L- and/or D-amino acids and combinations thereof, which affect myeloid cells by action on the triggering receptors expressed on myeloid cells (TREMs), including TREM-1 and TREM-2. The peptides act on the TREM/DAP-12 signaling complex. Also provided are lipid and sugar conjugated peptides comprising L- or D-amino acids. A method is provided of designing the peptides and lipid- and/or sugar-conjugated peptides comprising L- or D-amino acids. The disclosure relates to the therapy of various myeloid cell-related disease states involving the use of these peptides and compounds. The peptides and compounds are useful in the treatment and/or prevention of a disease or condition where myeloid cells are involved or recruited. The peptides of the present invention also are useful in the production of medical devices comprising peptide matrices (for example, medical implants and implantable devices).