In this study, we showed an increasing frequency of MDSCs in peripheral blood of chronic brucellosis patients (Figure 1B), which might be associated with an immunosuppressive status of chronic brucellosis patients (Groth et al., 2019), who had the higher level of serum IL-10 and TGF-β compared to healthy individuals (Figures 2B, C). This evidence concerns the gene TGFB1 and brucellosis.