ARG1 and Sepsis: Within the sepsis group, non-survivors had a significantly higher percentage of PMN-MDSC-like cells than survivors (P = 0.012).<h4>Conclusion</h4>In the early stage, septic patients exhibit a distinct response profile of myeloid cells with MDSC phenotypes compared to non-septic patients, characterized by attenuated expansion of total MDSC-like cells and M-MDSC-like cells but enhanced ARG-1 expression, alongside more severe inflammation, organ dysfunction, and lymphopenia.