P4 Peptide in Community Acquired Pneumonia

The investigators' aim is to find out whether immune cells from patients with a severe chest infection will react ex vivo to a new immunomodulating peptide, P4 as part of augmented passive immunotherapy The investigators know that P4 treatment can successfully improve the efficiency of specialized immune cells responsible for killing bacteria. The investigators also know that P4 treatment is effective in healthy human volunteers but wish to extend this observation to patients that have infection, as immune cells may react differently in these patients. If this study is successful, the investigators hope to be moving closer to a new treatment against severe bacterial infections. The investigators plan to recruit patients admitted to the Intensive Care Unit (ICU) and healthy volunteers, using carefully established inclusion and exclusions criteria with severe community acquired pneumonia (CAP) and obtain both blood and (if clinically feasible), a bronchoscopy BAL sample (washing of lung tissue).