Low Dose of IL-2 In Acute Respiratory DistrEss Syndrome Related to COVID-19

About 25% of hospitalized patients with SARS-CoV2 infection presented life-threatening respiratory conditions. Of these, 60% met ARDS criteria leading to death in 25% to 63% of the cases. SARS-CoV2-related ARDS is caused by a massive inflammatory cell infiltration leading to dysregulated cytokine/chemokine responses with lung immunopathological changes. To date, there is no treatment available. Regulatory T cells (Treg) are a subpopulation of CD4+ T cells playing a crucial role in the control of immune responses, in part by preventing excessive inflammation. Depletion of Treg cells in models of lung infection or after berylium exposure exacerbated lung inflammation. In contrast, a beneficial role for Treg during early ARDS and its resolution has been observed. Low-dose interleukin 2 (Ld-IL2) is the first therapy driving Treg-specific expansion and activation. Ld-IL2 was successfully tested in a wide range of preclinical models of inflammatory diseases, including beryllium-induced lung inflammation. Moreover, Ld-IL2 has been shown to be safe and free of serious adverse events when administered in patients with various autoimmune diseases. Importantly, in our previous work, we observed only very low concentrations of IL-2 in the blood (0.1 pg/mL \[0.0-2.0\]) as well as in the BAL supernatant (0.8 pg/mL \[0.4-1.3\]) collected from patients during the early phase of ARDS, suggesting that additional IL-2 could be beneficial for Treg expansion/activation. Our objective is therefore to investigate the therapeutic benefit of Ld-IL2 as a Treg inducer for controlling SARS-CoV2-related ARDS. After admission of patients to the intensive care unit at one of the recruiting centers, the eligibility criteria will be checked by the investigating physician and participation in the study will be proposed to the patient or parent/family member/trusted person. If the patient is unable to consent and there is no parent/family member/trusted person, the patient may be included in the emergency procedure. After inclusion (J0), the patient will be randomized to one of the 2 treatment arms (low dose IL-2 or placebo). The experimental treatment will be daily administered to the patient from D1 to D10. The patient will be monitored daily until D28 during hospitalization.