Characterization of immune-related genes and immune infiltration features for early diagnosis, prognosis and recognition of immunosuppression in sepsis

•Based on machine learning approach, IRG classifier was constructed.•IRG classifier could be robust tool to diagnose sepsis earlier.•IRG classifier can identify patients at risk of a poor or even fatal outcome.•IRG classifier is closely correlated with responses to hydrocortisone.•IRG classifier could efficiently reflect immunological status.