Abstract
OBJECTIVE: To evaluate gene expression in blood of patients with psoriatic arthritis (PsA) versus healthy controls and identify changes associated with guselkumab treatment. METHODS: Whole blood transcriptome profiling via paired-end RNA sequencing was conducted using samples from DISCOVER-1 and DISCOVER-2 at baseline (n = 673) and at weeks 4 and 24 from a representative subgroup that received placebo or guselkumab (n = 227 [longitudinal PsA cohort]). Baseline samples were compared with demographically matched healthy controls (n = 21). Guselkumab-mediated changes in gene expression were assessed in participants from the longitudinal PsA cohort who did versus did not achieve at least 20% improvement in American College of Rheumatology response criteria (ACR20) or at least 75% improvement in Psoriasis Area and Severity Index (PASI75). Differential gene expression was analyzed using edgeR. RESULTS: At baseline, 355 upregulated and 314 downregulated genes (PsA-associated genes) were identified in patients with PsA versus healthy controls. Upregulated genes were related to neutrophil, mononuclear cell, and CD11b+ gene sets. No cell type-specific gene sets were identified among downregulated genes. Most PsA-associated genes were modulated by guselkumab treatment. At week 24, genes downregulated by guselkumab were enriched with neutrophil, monocyte, eosinophil, and macrophage gene sets; genes upregulated by guselkumab were enriched with B cell, T cell, and natural killer cell gene sets. Reductions in expression of upregulated PsA-associated gene sets were more pronounced in ACR20 and PASI75 responders than in nonresponders. CONCLUSION: These findings suggest a dysregulation of immune cell profiles in blood from patients in the baseline PsA cohort that approached levels in healthy controls after guselkumab treatment.