Low-dose interleukin-2 therapy in refractory systemic lupus erythematosus: an investigator-initiated, single-centre phase 1 and 2a clinical trial  Jens Y Humrich, MD, Caroline von Spee-Mayer, PhD, Elise Siegert, MD, Martina Bertolo, MD, Angelika Rose, PhD, Dimas Abdirama, PhD, Philipp Enghard, MD, Bruno Stuhlmüller, PhD, Prof Birgit Sawitzki, PhD, Dörte Huscher, PhD, Prof Falk Hiepe, MD, Tobias Alexander, MD, Prof Eugen Feist, MD, Prof Andreas Radbruch, PhD, Prof Gerd-Rüdiger Burmester, MD, Prof Gabriela Riemekasten, MD  The Lancet Rheumatology  Volume 1, Issue 1, Pages e44-e54 (September 2019) DOI: 10.1016/S2665-9913(19)30018-9 Copyright © 2019 Elsevier Ltd Terms and Conditions

Figure 1 Assessment of regulatory T-cell responses (A) Changes in the proportion of CD25hi-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells in each treatment cycle and between baseline and day 62. Exact p values are listed in the appendix (p 22). (B) Relation between within-cycle changes in the proportion of CD25hi-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells and cumulative dose of IL-2 per cycle. (C) Changes in the proportion of Ki67-expressing regulatory T cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells in each treatment cycle and between baseline and day 62. Exact p values are listed in the appendix (p 22). (D) Relation between within-cycle changes in the proportion of Ki67-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells and cumulative dose of IL-2 per cycle. (E) Changes in the ratio of Ki67-expressing regulatory T cells to Ki67-expressing conventional T cells in each treatment cycle and between baseline and day 62. Exact p values are listed in the appendix (p 22). (F) Relation between within-cycle changes in the proportions of Ki67-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells and within-cycle changes in the proportions of CD25hi-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells. For (A, C, E), data are median (n=12); error bars show IQR; the shaded areas show the treatment cycles. The Wilcoxon signed-rank test was used to calculate significance. For (B, D, F), we used Spearman's rank correlation coefficients to calculate correlations. Treg=regulatory T cells. Tcon=conventional T cells. FC=median fold-change. *p<0·001 compared with start of treatment cycle. †p<0·001 compared with baseline. ‡p<0·01 compared with start of treatment cycle. §p<0·01 compared with baseline. ¶p<0·05 compared with start of treatment cycle. ||p<0·05 compared with baseline. The Lancet Rheumatology 2019 1, e44-e54DOI: (10.1016/S2665-9913(19)30018-9) Copyright © 2019 Elsevier Ltd Terms and Conditions

Figure 2 Clinical responses (A) Changes in SELENA-SLEDAI scores in individual treated patients (n=12). Exact p values are listed in the appendix (p 24). (B) Changes in SELENA-SLEDAI scores between baseline and day 62 in individual patients (n=12). The values for patients EE and HH were identical at baseline and day 62, as were those for patients FF and P2, such that the datapoints for these patients overlap completely. (C) Median changes in SELENA-SLEDAI scores in clinical responders during the study (n=8). Error bars show the IQR; the shaded areas show the treatment cycles. Exact p values are listed in the appendix (p 24). (D) Changes in concentrations of complement factor C3 between baseline and day 62 in individual patients (n=12). The Wilcoxon signed-rank test was used to calculate p values for parts (A)–(D). (E) Comparison of proportions of CD25hi-expressing cells and CD137-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells between clinical responders (n=8) and non-responders (n=4) at day 62. The line represents the median. We used the Mann-Whitney test to calculate p values. (F) Correlation of the changes in the proportion of CD25hi-expressing cells among CD3 + CD4 + FOXP3 + CD127lo regulatory T cells between baseline and day 62 and the change in SELENA-SLEDAI scores between baseline and day 62. We used Spearman's rank correlation coefficients to calculate correlations. Treg=regulatory T cells. SELENA-SLEDAI=Safety of Estrogens in Lupus National Assessment-Systemic Lupus Erythematosus Disease Activity Index *p<0·05. †p<0·01. The Lancet Rheumatology 2019 1, e44-e54DOI: (10.1016/S2665-9913(19)30018-9) Copyright © 2019 Elsevier Ltd Terms and Conditions