Evaluation of a Functional Lymphocyte Test (QuantiFERON Monitor®) as a Prognostic Marker for Acute Community-acquired Pneumonia

Lower respiratory infections, or pneumonia, remain the third leading cause of death worldwide, despite progress in vaccinating at-risk populations and improved resuscitation techniques. Research shows that immune defences are weakened during severe infections. This immune weakening could alter resistance to bacterial infection and facilitate death, but also facilitate the onset of secondary infections. Through this study, investigators wish to evaluate a biomedical test (derived from a blood sample - Quantiferon Monitor test), aimed at measuring the immune response of certain immune cells (lymphocytes). The objective of the study is to determine whether this test can predict the occurrence of death during pneumonia. If this hypothesis is verified, it would make it possible to use this test as a marker to identify patients at risk of death, and would open up new therapeutic prospects in order to provide patients with severe pneumonia with a treatment that stimulates their immune defences. Recently, COVID-19 has changed the epidemiology and management of acute community-acquired pneumonia. Numerous studies, including some recently published ancillary studies of the Lymphony study, suggest that a deregulated immune response could contribute to the poor patient prognosis. Different determinants could contribute to this. Endotoxemia reflects the elevation of plasma LPS concentrations and represents a major Gram-negative determinant. Endotoxemia also seems to be observed during infectious pneumopathies, even though the main causative agents are devoid of LPS. The genesis of this endotoxemia and its intensity could reflect a digestive bacterial translocation phenomena that is correlated with severity. Concerning the secondary objectives of the COVITOXEMIA ancillary study: the main hypothesis is that severe pneumopathies related to SARS-CoV2- are associated with endotoxemia. Furthermore, early work comparing the immune response during severe SARS-CoV-2-related lung d