However, the clinical significance of TLR4<sup>+</sup>MDSC and PD-L1<sup>+</sup>MDSC in <i>Brucella</i> infection remains unclear.<h4>Methods</h4>A total of 88 patients with acute brucellosis infection (ABI), 66 patients with chronic brucellosis infection (CBI), and 82 healthy controls (HC) subjects were enrolled. Here, TLR4 is linked to infection.