Maryann Whitley

Divergent Phenotypes of Human Regulatory T Cells Expressing the Receptors TIGIT and CD226

Regulatory T cells (Tregs) play a central role in counteracting inflammation and autoimmunity. A more complete understanding of cellular heterogeneity and the potential for lineage plasticity in human Treg subsets may identify markers of disease pathogenesis and facilitate the development of optimized cellular therapeutics. To better elucidate human Treg subsets, we conducted direct transcriptional profiling of CD4+FOXP3+Helios+ thymic-derived Tregs and CD4+FOXP3+Helios− T cells, followed by comparison with CD4+FOXP3−Helios− T conventional cells. These analyses revealed that the coinhibitory receptor T cell Ig and ITIM domain (TIGIT) was highly expressed on thymic-derived Tregs. TIGIT and the costimulatory factor CD226 bind the common ligand CD155. Thus, we analyzed the cellular distribution and suppressive activity of isolated subsets of CD4+CD25+CD127lo/− T cells expressing CD226 and/or TIGIT. We observed TIGIT is highly expressed and upregulated on Tregs after activation and in vitro expansion, and is associated with lineage stability and suppressive capacity. Conversely, the CD226+TIGIT− population was associated with reduced Treg purity and suppressive capacity after expansion, along with a marked increase in IL-10 and effector cytokine production. These studies provide additional markers to delineate functionally distinct Treg subsets that may help direct cellular therapies and provide important phenotypic markers for assessing the role of Tregs in health and disease.

Tofacitinib attenuates pathologic immune pathways in patients with psoriasis: A randomized phase 2 study

BACKGROUND Tofacitinib is an oral Janus kinase inhibitor being investigated for psoriasis. OBJECTIVE We sought to elucidate the molecular mechanisms underlying the clinical efficacy of tofacitinib in patients with psoriasis. METHODS Twelve patients with plaque psoriasis were randomized (3:1) to receive 10 mg of tofacitinib or placebo twice daily for 12 weeks. Biopsy specimens were taken from nonlesional (baseline) and lesional (baseline, days 1 and 3, and weeks 1, 2, 4, and 12) skin. Biopsy specimens were examined for psoriatic epidermal features (thickness, Ki67(+) keratinocytes and keratin 16 [KRT16] mRNA expression, and phosphorylated signal transducer and activator of transcription [pSTAT](+) nuclei) and T-cell and dendritic cell (DC) subsets by using immunohistochemistry, and mRNA transcripts were quantified by using a microarray. RESULTS In lesional skin keratinocyte pSTAT1 and pSTAT3 staining was increased at baseline but reduced after 1 day of tofacitinib (baseline, median of 1290 pSTAT1(+) cells/μm(2); day 1, median of 332 pSTAT1(+) cells/μm(2); and nonlesional, median of 155 pSTAT1(+) cells/μm(2)). Epidermal thickness and KRT16 mRNA expression were significantly and progressively reduced after days 1 and 3 of tofacitinib administration, respectively (eg, KRT16 decreased 2.74-fold, day 3 vs baseline, P = .016). Decreases in DC and T-cell numbers were observed after weeks 1 and 2, respectively. At week 4, significant decreases in IL-23/TH17 pathways were observed that persisted through week 12. Improvements in clinical and histologic features were strongly associated with changes in expression of psoriasis-related genes and reduction in IL-17 gene expression. CONCLUSIONS Tofacitinib has a multitiered response in patients with psoriasis: (1) rapid attenuation of keratinocyte Janus kinase/STAT signaling; (2) removal of keratinocyte-induced cytokine signaling, leading to reductions in pathologic DC and T-cell numbers to nonlesional levels; and (3) inhibition of the IL-23/TH17 pathway.

The Biomarkers of Lupus Disease Study: A Bold Approach May Mitigate Interference of Background Immunosuppressants in Clinical Trials

Molecular medicine raised expectations for strategically targeted biologic agents in systemic lupus erythematosus (SLE), but clinical trial results have been disappointing and difficult to interpret. Most studies add investigational agents to various, often effective, standard therapy immunosuppressants used at baseline, with unknown treatment interactions. Eliminating polypharmacy in trials of active lupus remains controversial. We undertook the Biomarkers of Lupus Disease study to test withdrawal of immunosuppressants as a novel approach to rendering SLE trials interpretable.

FRI0003 Determination of interferon (IFN) signatures for sle patients may be critical for optimal treatment selection but depends on the genes chosen: report from the bold (biomarkers of lupus disease) study

Background Elevated expression of IFN pathway genes, known as the IFN signature (IS) is found in roughly half of SLE patients1. Various studies have used different IFN genes to define the IS, and different methods to assign patients to “IFN high” or “low” expression groups. Importantly a recent report from the Genentech ROSE study found higher responsiveness to an interferon antagonist in patients with lower IFN expression using a 7 gene set (G-7), suggesting that IS might inform optimal selection of treatments in the future2. Objectives As a step toward understanding the clinical relevance and molecular drivers of the IS, we used data from the BOLD study to test the difference between IS-derived patient groupings derived from different sets of IFN genes. Methods The BOLD study enrolled SLE patients with active disease (minimum SLEDAI of 6 or two BILAG B scores). 41 patients had background immune suppressives withdrawn, were given brief steroids until improvement, then followed with serial samples until disease flare. 62 additional active SLE patients were evaluated only once. RNA expression levels for 329 genes were assayed using TaqMan® Low Density Arrays. 238 SLE patient-visits were partitioned into two groups by unsupervised hierarchical clustering of the expression levels of IFN-related genes. Results Clustering was done separately for 5 gene sets, denoted B-30, P-11, M-20, G-7, and O-3. Two of the gene sets (M-20 and G-7) were 95% and 100% matched to sets used in clinical trials of IFN-inhibiting treatments. Consistent with previous reports, all of the gene sets assigned about 40-50% of visits (96 to 118 patient-visits) to an “IFN high” group characterized by IFN pathway expression that was higher than healthy volunteers. In a cross-sectional analysis using the P-11 gene set, membership in the IFN high group was associated with higher SLEDAI score than IFN low assignment (9.73 vs. 7.70, p<0.0001) and higher TNFSF13B (BLYS/BAFF) gene expression (2.4 fold increase, p=0.0005). Most of the patients followed longitudinally remained in the same group over the course of the study, despite changes of gene expression with disease improvement and flare. IFN group assignments were similar for the B-30 and P-11 gene sets, and also similar among the M-20, G-7, and O-3 gene sets, but differed more across these groups. For instance, 21 patient-visits (9%) were assigned to the IFN high group by the G-7 gene set, but placed in the IFN low group by the P-11 gene set. Conclusions The comparison of IFN group assignments for the same samples, derived using different IFN gene sets, highlights the need for more investigation of the molecular and cellular drivers of IFN gene expression in SLE blood. An optimal IFN gene set, once determined, might improve how patients are selected for targeted therapies in the future. References Baechler et al., PNAS 100(5) 2610-2615 (2003); Kalunian et al., ACR 2012 Washington D.C, Abstract 2622. Disclosure of Interest None Declared