Our data suggest that Helios-expressing Foxp3(+) Treg with functional suppressive capacity and migratory potential into inflamed tissues are expanded in active SLE, presumably through γ-chain signalling cytokines and TCR stimulation, to compensate for autoreactive effector responses.

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BackgroundOver the past 20 years, hematopoietic stem cell transplantation (HSCT) has been emerging as a promising treatment option for severe cases of autoimmune diseases (ADs). Meanwhile, positive results have been obtained in 3 randomised clinical trials for systemic sclerosis. The goal of this therapy is to induce medication-free remissions by ablating the pathologic autoreactive memory and restoring of self-tolerance.ObjectivesHere, we summarise the clinical outcomes of AD patients receiving HSCT at the Charité – University Medicine.MethodsIn this prospective study, the outcome of 22 patients been analysed after receiving a CD34+-selected autologous HSCT after immunoablation with ATG and cyclophosphamide for different ADs (10 SLE, 4 SSc, 3 vasculitis, 2 multiple sclerosis, 1 polychondritis, 1 inflammatory polyneuropathy, 1 autoimmune haemolytic anaemia) between 1998 and 2015. Multiparamteric flow cytometry was applied to characterise peripheral blood lymphocytes subsets including analysis of the TCR-Vbeta repertoire on CD4+ T cells, CD31 expression as marker for thymic output of CD4+ T cells, including Foxp3+ Tregs. In SLE, Siglec-1 on monocytes as surrogate for interferon activity and RNA expression profiling by microarray of FACS-sorted CD14+ monocytes was performed (Affymetrix). Autoantibodies were investigated with ELISA.ResultsWith a median follow-up of 135 months, the overall survival was 76.5% and progression-free survival 67.9%, respectively. 3 deaths were regarded treatment related, 1 patient had persisting disease (haemolytic anaemia) and 4 relapses occurred in SLE at 1, 18, 36 and 80 months, respectively. Remaining patients are in stable clinical remissions despite discontinuation of immunosuppressive therapy. HSCT was associated with significant reduction or normalisation of autoantibody levels and a profound reconfiguration of the adaptive immune system, the latter characterised by a re-emergence of naïve T cells with markers of recent thymic emigrants and renewed TCR repertoire, including Foxp3+ Tregs and regeneration of naïve B cells. In SLE patients, Siglec-1 expression on monocytes completely normalised and transcriptome analysis revealed an abrogation of type I interferon signalling in responding patients.ConclusionsOur data provide the …proof-of-concept“ that a chronic autoimmune system can be reset into a naïve and self-tolerant state by HSCT, potentially providing cure in AD. Although applied as salvage therapy in severely affected patients with poor outcomes, TRM gradually improved due to accumulating centre experience and better patient selection and supportive care. Based on positive results from RCT in the major indications, HSCT should be placed earlier in the treatment algorithm, especially in systemic sclerosis with rapid progress and lung involvement.Disclosure of InterestNone declared

ObjectivesThe authors aimed to analyse the coexpression level of Helios, a member of the Ikaros transcription factor family, in FoxP3 + regulatory T cell (Treg) subsets to characterise the pool of circulating natural Tregs in patients with systemic lupus erythematosus (SLE). Methods Multicolour fl ow cytometry was performed to analyse the coexpression of Helios, CD25, CD45RA and CD31 in FoxP3 + Tregs from peripheral blood of 20 patients with SLE, 20 age-and sex-matched healthy controls (HC), 6 patients after thymectomy for myasthenia gravis and 6 patients after receiving immunoablation and autologous stem cell transplantation (ASCT) for SLE. Statistical analyses were performed using the paired t-test. Findings The level of circulating FoxP3 + T cells among CD4 T cells was signifi cantly higher in SLE compared to HC (mean 14.5 vs 7.2%, p=0.002) with Helios being coexpressed at significantly higher levels in SLE (81.4 vs 69.0%, p=<0.0001). With respect to CD45RA coexpression, CD4 + FoxP3 + T cells can be subdivided into three distinct subpopulations, all of which are present at signifi cantly higher levels among CD4 T cells in SLE: CD45RA + FoxP3lo resting Tregs (p=0.01), CD45RA − FoxP3hi activated Tregs (p=0.01) and CD45RA − FoxP3lo nonTreg cells (p=0.004). In SLE, Helios expression levels were signifi cantly higher in all of these subsets compared to HC: 90.7 versus 85.1% in CD45RA + FoxP3lo Tregs (p=0.003), 83.3 versus 74.7% in CD45RA − FoxP3hi Tregs (p=0.003) and 73.8 versus 52.5% in CD45RA − FoxP3lo non-Treg cells (p<0.0001). Within the CD45RA + FoxP3lo Treg subset, the coexpression level of CD31 was signifi cantly lower in SLE (p=0.03) and patients after thymectomy (p=0.001), but higher in patients after ASCT who developed a thymic reactivation (p=0.04). Conclusion The authors' data are the fi rst to demonstrate that circulating Helios + FoxP3 + natural Treg levels are signifi cantly increased in SLE patients compared to healthy controls. This does, however, not necessary refl ect an increased thymic output of natural Tregs in SLE. The decreased coexpression levels of CD31, as a surrogate marker for recent thymic emigrants, found among CD45RA + FoxP3 + Tregs in SLE rather suggests that the thymic output is diminished in SLE implicating that Treg levels are primarily maintained through peripheral expansion of Helios + FoxP3 + Tregs in SLE. The level of Helios − FoxP3 + induced Tregs are, on the other hand, decreased in SLE for so far unknown reasons. on 12 May 2018 by guest. Protected by copyright.