Table 1.

Study inclusion and exclusion criteria according to groups

Criteria	Sepsis	SIRS	Pneumonia	Localized infection	Healthy controls
Inclusion	Sepsis or septic shock according to SEPSIS-3 criteria [15]	Systemic inflammatory response after major surgery and cardiopulmonary bypass (modified SEPSIS-2 criteria)	ICU or IMC patients with community-acquired pneumonia without recent hospitalization or association with other healthcare facilities such as nursing homes, dialysis centers, and outpatient clinics Clinical symptoms like fever, cough or dyspnea and a CURB-65 score ≥ 1 were required for diagnosis	ICU/IMC patients with large peripheral tissue infections (e.g., abscess formation after i.v. drug abuse)	Charlson Comorbidity Index = 0 [41]
Exclusion	No consent given by patients or next-of-kin
	Age < 18
	Pregnancy
	Preexisting chronic infectious disorders (e.g., endocarditis, HIV or hepatitis)
	Current tumor or malignant disorders
	Limited patient’s life expectancy < 6 months (independent of, e.g., sepsis/SIRS, pneumonia or localized infection)
	Immunosuppressiona

ICU  intensive care unit, IMC intermediate care

^aPatients being on steroid therapy, autoimmune disease, transplantation or other immunocompromising conditions like HIV or leukemia