Treatment of the Bilateral Severe Uveitis by IVT of Regulator T-cells: Study of Tolerance of Dose

Arsenal and limitations in the treatment of uveitis Uveitis is a major cause of severe visual loss or even blindness in children and young adults. In almost one third of cases, it is associated with an infectious agent, another third is integrated in the field of autoimmune diseases as systemic entities including (Behçet's disease, sarcoidosis, spondyloarthropathy ...) or limited to the eye (Birdshot type retinochoroidopathy, sympathetic ophthalmia, idiopathic retinal vasculitis). The last third remains idiopathic, where despite a careful etiological research, no cause is identified. The systemic corticosteroids are often effective but have significant side effects and patient compliance is often poor. That is why they are sometimes administered directly into the posterior segment of the eye (vitreous), but the effect is only temporary, often ineffective, and also associated with side effects. In addition, some are steroid-dependent, requiring treatment with immunosuppressive agents; which also may be responsible for many adverse effects and are not always effective. In these therapeutic impasse situations, investigators propose a cell therapy approach injection of CD4 + CD25 + Foxp3 regulators + (Tregs), directly into the vitreous of patients.

A new therapy approach uveitis by cell therapy It is now clearly established that Tregs play a critical role in the control of autoimmune diseases. In man or mouse, a deep deficit in Tregs is associated with a very severe autoimmune syndrome, leading to death .In uveitis, it is also shown that Tregs control this disease in deficient mice. Tregs have been reported in humans . In addition, our group and others have shown that various autoimmune diseases can be prevented by transfer of Tregs in mice .Thus, cell therapy by injection of Tregs raises hopes for the treatment of chronic inflammatory and autoimmune diseases . However, only specific and not polyclonal Tregs, have a strong therapeutic potential when administered systemically. The only Tregs that can be used in clinic are polyclonal Tregs purified by magnetic beads to which, are adsorbed anti- CD25 antibody . This technology provides a cell preparation enriched in Tregs for 50 to 70%, the balance consisting of effector T cells (Teffs ) , B lymphocytes and NK cells. A therapeutic alternative to the systemic injection of specific Tregs is to inject, preactivated polyclonal Tregs directly into the target site of autoimmune disease, in purified clinical grade condition.

Description of the study population. Patients with bilateral severe steroid-dependent non-infectious uveitis. Infectious or tumoral etiologies have been excluded after completion of a comprehensive review of systems. All patients had a negative Quantiferon test and a normal Mantoux test. Biological tests sent to specialized laboratories will eliminate an active infection. In some cases, aqueous humor obtained after AC tap and / or vitreous biopsy obtained after vitrectomy will be analyzed for diagnostic assay IL-10, immune load factor or PCR analysis (toxoplasmosis, herpes viruses).

Pathophysiology of uveitis in humans. Inflammatory chemokines and cytokines, such as IL-6, IFN-g, IL-8 and MCP-1 and sometimes IL-1ß, IL-2 and TNF-alpha were found in the aqueous humor and vitreous of patients with uveitis . Given the small volume available in these human samples (around 100 ml), data are obtained with multiple detection techniques using flow cytometry, for measuring the concentration of thirty different cytokines and chemokines in a 50 microl volume.

In order to expand the study to other cytokines and chemokines, investigators also used a semi-quantitative technique named ""antibody array"" which allows the analysis of a number of different molecules ranging from 30 to 170. These preliminary results, evaluated in some patients, confirm the presence of Th1 inflammatory profile in the eye of patients suffering from uveitis (not shown) and confirm our strategy