Thus,we decided to investigate the influence of E. coli LPS on CD25expression and CD80/CD28 costimulation of PHA-stimulated peripheralblood mononuclear cells (PBMCs) from brucellosis patients and compare the findings with our previousresults regarding the HKBA stimulation of PBMCs in the same groups of patients[23]. Here, CD28 is linked to brucellosis.