Immune Regulatory 1 Cells: A Novel and Potent Subset of Human T Regulatory Cells.

A subset of T regulatory cells (Tregs), identified by TIRC7 (T cell immune response cDNA 7) expression is designated as Immune Regulatory 1 Cells (IR1 cells). TIRC7 is an immune checkpoint inhibitor, co-localized with the T- cell receptor, HLA-DR and CTLA-4 during T-cell activation, which delivers regulatory signals via binding to its ligand, HLA-DR α2 domain. IR1 cells express FOXP3, and multiple other markers associated with immune suppression. They constitute as much as 10% of Tregs. IR1 cells strongly inhibit proliferation in mixed lymphocyte reactions, where they express high levels of IL-10. Ex vivo expansion of Tregs over 2 weeks in the presence of an agonist TIRC7 antibody disproportionately expands the IR1 Treg subset, while maintaining high expression of suppressive markers including CD39, IL-10, LAP and GARP. Ex vivo expanded IR1 cells are a potent, homogeneous, stable set of suppressor Tregs with the potential to modulate immune dysregulation. The characteristics of IR1 cells suggest a therapeutic advantage over polyclonal Tregs for therapeutic interventions. Early restoration of immune homeostasis using IR1 cells has the potential to fundamentally alter the natural history of conditions characterized by abnormalities in the T regulatory cell compartment.

Improved Survival in Liver Transplant Patients Receiving Prolonged-release Tacrolimus-based Immunosuppression in the European Liver Transplant Registry (ELTR): An Extension Study.

BACKGROUND: We compared, through the European Liver Transplant Registry, long-term liver transplantation outcomes with prolonged-release tacrolimus (PR-T) versus immediate-release tacrolimus (IR-T)-based immunosuppression. This retrospective analysis comprises up to 8-year data collected between 2008 and 2016, in an extension of our previously published study. METHODS: Patients with <1 month follow-up were excluded; patients were propensity score matched for baseline characteristics. Efficacy measures included: univariate/multivariate analyses of risk factors influencing graft/patient survival up to 8 years posttransplantation, and graft/patient survival up to 4 years with PR-T versus IR-T. Overall, 13 088 patients were included from 44 European centers; propensity score-matched analyses comprised 3006 patients (PR-T: n = 1002; IR-T: n = 2004). RESULTS: In multivariate analyses, IR-T-based immunosuppression was associated with reduced graft survival (risk ratio, 1.49; P = 0.0038) and patient survival (risk ratio, 1.40; P = 0.0215). There was improvement with PR-T versus IR-T in graft survival (83% versus 77% at 4 y, respectively; P = 0.005) and patient survival (85% versus 80%; P = 0.017). Patients converted from IR-T to PR-T after 1 month had a higher graft survival rate than patients receiving IR-T at last follow-up (P < 0.001), or started and maintained on PR-T (P = 0.019). One graft loss in 4 years was avoided for every 14.3 patients treated with PR-T versus IR-T. CONCLUSIONS: PR-T-based immunosuppression might improve long-term outcomes in liver transplant recipients than IR-T-based immunosuppression.