In Vitro Effect Study of Interleukin-2 Muteins on Regulatory T Cells of Patients With Different Autoimmune, Allo-immune or Inflammatory Diseases

Interleukin 2 (IL-2) is a critical cytokine for the survival and function of regulatory T cells (LTreg). This cytokine has a dual role in the immune system. IL-2 stimulates immune responses by acting on the intermediate affinity IL-2R receptor, IL-2Rβγ, expressed by conventional T cells (LTconv) during activation, but also contributes to the inhibition of immune responses via LTreg that express the high affinity receptor IL-2Rαβγ. This difference in IL-2 receptor affinity for IL-2 has led to the development of low-dose IL-2 therapy to stimulate LTreg and improve control of excessive inflammation in autoimmune (AID), inflammatory or alloimmune diseases Low-dose IL-2 therapy is being studied in several of these diseases such as systemic lupus erythematosus, type 1 diabetes, alopecia, HCV (hepatitis C virus)-induced vasculitis, atopic dermatitis and chronic allo-transplantation-related graft-versus-host disease (GVHD). Some of these studies have shown an increase in LTreg numbers and an improvement in certain clinical signs. To improve LTreg targeting in autoimmune diseases, inflammatory diseases or GVHD, mutated IL-2s (muteins) have been developed with selective LTreg agonist properties. These IL-2 muteins are linked to an Fc fragment to increase their half-life. Two IL-2 variants (IL-2Vs)-Fc preferentially stimulate STAT5 phosphorylation in LTregs compared to conventional FoxP3- (LTconv) CD4+ or CD8+ T cells

Hypothesis: In order to confirm that this differential effect of IL-2 muteins, already established in non-diseased controls, is also observed in patients with autoimmune diseases, inflammatory diseases or GVHD, a pilot in vitro study should be conducted on a small number of patient's blood samples (5 or 10 depending on the pathology). Objective : Conduct a multicentre pilot study to confirm the hypothesis that IL-2 muteins preferentially activate the STAT5 pathway in LTreg compared to LTconv in patients with GVHD, acquired bone marrow aplasia, systemic lupus erythematosus, multiple sclerosis, rheumatoid arthritis, autoimmune thyroiditis, vitiligo, alopecia or atopic dermatitis Method: At the inclusion, patients will have a blood sample collected for in vitro research purposes. Their clinical data will also be collected. Conclusion This trial should provide in vitro proof-of-principle of the efficacy of IL-2 muteins on LTreg and could eventually lead to a therapeutic trial