Increased levels of circulating Helios+ FoxP3+ natural regulatory T cells in systemic lupus erythematosus

Objectives The 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 flow 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 significantly 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=