Assessing Immune Dysfunction in Sepsis

ICU With Sepsis Inclusion Criteria: * Age ≥ 18 * Presumed diagnosis of sepsis, defined as "patients with life-threatening organ dysfunction caused by a dysregulated host response to infection" * Patients in the ICU who meet 2 or more of the quick SOFA (qSOFA) definition along with organ dysfunction: 1. Respiration rate ≥ 22 breaths/min and/or mechanically ventilated 2. An alteration in mental status 3. Systolic blood pressure of less than 100 mm Hg and/or receiving inotropes to maintain blood pressure AND/OR <!-- --> 1. An acute change in SOFA score ≥2 points, consequent to the infection (can assume SOFA score = 0 in patients with no pre-existing organ dysfunction) ICU Without Sepsis Inclusion Criteria: * Age ≥ 18 * Patients requiring care at a M Health Fairview ICU due to high acuity of illness and no other evidence of sepsis Healthy Volunteer Inclusion Criteria * Age greater or equal to 18 * ASA status 1, 2 or 3 * May include patients who are receiving dialysis in an outpatient setting Exclusion Criteria (all groups): * Active cancer with chemotherapy and/or radiation treatment within the past 6 weeks * Medication usage that includes immunosuppressive drugs, biologic agents, cytokines, growth factor and interleukins * Steroid medication usage of \&gt; 300mg hydrocortisone per day (equivalent of \&gt; 20mg prednisone). Patients with chronic steroid use will be excluded, however patients who have had stress dose steroids administered following admission will be included. * Patients with a history of, or who currently have evidence of autoimmune disease, including but not limited to: myasthenia gravis, Guillain Barré syndrome, systemic lupus erythematosus, multiple sclerosis, scleroderma, ulcerative colitis, Crohn's disease, autoimmune hepatitis, Wegener's granulomatosis, HIV/AIDS, etc. * Patients with active or a history of acute or chronic lymphocytic leukemia * Known history of chronic hepatitis B (HBV) infection and not on treatment with HBV nucleoside analogues prior to the current hospitalization, or HBV DNA \&gt; 100 IU/mL * Known history of infection with hepatitis C (HCV) and currently undergoing treatment for HCV infection or has detectable HCV RNA * Participation in another investigational interventional drug study within the past 4 weeks * Current pregnancy * Current incarceration