The aim of the study is to conduct one RCT of personalized immunotherapy in sepsis targeting patients who lie either on the predominantly hyper-inflammatory arm or on the predominantly hypo-inflammatory arm of the spectrum of the host response. These patients will be selected by the use of a panel of biomarkers and laboratory findings and they will be randomly allocated to placebo or immunotherapy treatment according to their needs.

Sepsis is a life-threatening organ dysfunction that results from the dysregulated host response to an infection. Accumulating knowledge suggests that this dysregulated host response has a broad spectrum where some patients lie to the two extremes of this spectrum whereas the majority of patients lie in between. The first extreme encompasses patients who are dominated from a hyper-inflammatory response to an infectious insult. On the other extreme lie patients who do not have any hyper-inflammatory response; instead these patients are dominated by an exhausted immune response to an infectious stimulus. The remaining patients have features of both hyper- and hypo-inflammatory responses.

Randomized clinical trials (RCTs) that have investigated the effects of immunotherapy in sepsis have all failed to establish beneficial effects for the patients. The reasons for that are multiple but one of the most important is the current notion that sepsis is a complex disorder with heterogeneity regarding patient characteristics. Thus, it is necessary to try and find ways to personalise the immunomodulatory treatment of sepsis. In the clinical trial proposed here, two personalised approaches will be investigated.

Some 25 years ago, there were high expectations of the blockade of interleukin (IL)-1 in sepsis using the human recombinant IL-1 receptor antagonist, anakinra. The expectations were based on animal experiments as well as positive results in a single-centre clinical trial. However, in a large international trial, anakinra did not show benefit over placebo. Still, it became clear from this study, enrolling 906 patients that intravenous anakinra was a very safe drug: there was neither excess mortality in these critically ill patients, nor increased susceptibility to secondary infections. In a post-hoc analysis of this trial published in 2016, it was demonstrated that a subgroup of 34 patients showed a clinical picture compatible with macrophage activation syndrome. Since bone marrow was not performed in these patients, the investigators prefer to call this macrophage activation like syndrome (MALS). MALS is a dreaded complication with a mortality rate in the order of 70%. The post-hoc analysis showed that patients receiving anakinra had 30% significant survival benefit compared to those receiving placebo. From these data it can be concluded that it is important to recognize patients with this complication of sepsis and that anakinra might be a beneficial drug.

A survey of the database of sepsis patients in the Hellenic Sepsis Study Group revealed that 5% of the patients with septic shock suffered from MALS. It was found in this study that MAS can be easily and reliably diagnosed by measuring ferritin in the blood. A cut off of 4.420ng/ml had specificity more than 97%.

Another important clinical phenomenon in sepsis is that patients may run into a phase of immunoparalysis. In this situation, the immune cells do not produce any more proinflammatory cytokines and switch to production of anti-inflammatory cytokines such as IL-10; they also loose important functional markers such HLA-DR. Patients with immunoparalysis have a 50% risk of dying in the subsequent 28 days. There is evidence from preclinical studies and from the endotoxin challenge model in human volunteers that immunoparalysis is reversible at least to some extent. The best candidate drug for this would be interferon gamma (IFNγ). Immunosuppression established in healthy volunteers after experimental endotoxemia was reversed after administration of recombinant human interferon-gamma (rhIFNγ). rhIFNγ was also investigated for this purpose in nine patients at septic shock in a small open-label and non-randomized clinical trial; reversal of immunoparalysis was achieved. The extensive experience with IFNγ teaches that it is a safe drug, the main side effect being fever and flu-like syndrome, which can be mitigated by premedication with a prostaglandin inhibitor like paracetamol. In patients with autoimmune diseases like systemic lupus erythematosus (SLE) and multiple sclerosis flares of the disease induced by IFNγ have been described. So these diseases are contraindications for the drug.

The purpose of this study is to investigate in a randomised placebo-controlled clinical trial with a double-dummy design in patients with septic shock, whether personalised immunotherapy directed against either MALS or immunoparalysis is able to change the perspective for these critically ill patients.

MALS is considered as a more direct life-threatening manifestation of sepsis than immunoparalysis. For that reason all patients will be randomised with evidence of MALS for anakinra or placebo, irrespective the state of immunity as measured by HLA-DR positivity.

The aim of the study is to conduct one RCT of personalized immunotherapy in sepsis targeting patients who lie either on the predominantly hyper-inflammatory arm or on the predominantly hypo-inflammatory arm of the spectrum of the host response. These patients will be selected by the use of a panel of biomarkers and laboratory findings and they will be allocated to placebo or immunotherapy treatment according to their needs.

Inclusion Criteria:

• Age equal to or above 18 years
• Male or female gender
• In case of women, unwillingness to remain pregnant during the study period
• Written informed consent provided by the patient or by one first-degree relative/spouse in case of patients unable to consent
• Community-acquired pneumonia or hospital-acquired pneumonia or ventilator-associated pneumonia or primary bacteremia or acute cholangitis
• Sepsis defined by the Sepsis-3 definitions.
• Patients with laboratory diagnosis of MALS or hypo-inflammation (immune-paralysis) based on two consecutive blood sampling with 24 hours apart. MALS is defined as the presence of ferritin >4,420 ng/ml and hypo-inflammation as HLA-DR expression on CD14-monocytes (co-expression) less than 30%

Exclusion Criteria:

• Age below 18 years
• Denial for written informed consent
• Acute pyelonephritis or intraabdominal infection other than AC, meningitis or skin infection. It is explicitly stated that in the case of a patient with both AC and any other type of intraabdominal infection, the patient cannot be enrolled.
• Any stage IV malignancy
• Any do not resuscitate decision
• In the case of BSI, patients with blood cultures growing coagulase-negative staphylococci or skin commensals or catheter-related infections cannot be enrolled.
• Active tuberculosis (TB) as defined by the co-administration of drugs for the treatment of TB
• Infection by the human immunodeficiency virus (HIV)
• Any primary immunodeficiency
• Oral or IV intake of corticosteroids at a daily dose equal or greater than 0.4 mg prednisone or greater the last 15 days
• Any anti-cytokine biological treatment the last one month
• Medical history of systemic lupus erythematosus
• Medical history of multiple sclerosis or any other demyelinating disorder
• Pregnancy or lactation. Women of child-bearing potential will be screened by a urine pregnancy test before inclusion in the study