Psoriasis (PS) is a systemic, immune-mediated inflammatory disorder. However, the whole lymphocyte compartment and the potential pathologies of PS have not been fully characterized. In the present study, we examined whole lymphocyte subsets and signal transduction proteins using high-dimensional single-cell mass cytometry and a bioinformatics pipeline for an in-depth characterization of the immune cell subsets and protein profiles involved in pathways in the peripheral blood of patients with PS. We identified 15 major immune cell populations in T cell lineages and characterized various CD3 ⁺ CD4 ⁺ Th and CD3 ⁺ CD8 ⁺ T cytotoxic cell populations simultaneously across 24 leukocyte markers and 7 proteins related to the signal transduction pathways. High-dimensional analysis identified 3 new subsets that are abundant in PS peripheral blood, resembling CD3 ^– CD4 ⁺ lymphoid tissue inducer cells, Tc17 cells, and CD8 ⁺ CXCR3 ⁺ Tregs. We confirmed the CD3 ^– CD4 ⁺ cells, and their features and functions, in an independent PS cohort. The use of single-cell mass cytometry allows systemic-level characterization of lymphocyte subpopulations and dysregulated signaling pathways in the blood of patients with PS, identifying abnormalities of different immune cell subsets. We validated that the CD3 ^– CD4 ⁺ cells had elevated OX40 and decreased FRA2 expression, which were positively associated with the PS area and severity index.

Systemic juvenile idiopathic arthritis (sJIA) is a severe autoinflammatory disorder with a still not clearly defined molecular mechanism. To better understand the disease, we used scattered datasets from public domains and performed a weighted gene coexpression network analysis (WGCNA) to identify key modules and hub genes underlying sJIA pathogenesis. Two gene expression datasets, GSE7753 and GSE13501, were used to construct the WGCNA. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were applied to the genes and hub genes in the sJIA modules. Cytoscape was used to screen and visualize the hub genes. We further compared the hub genes with the genome‐wide association study (GWAS) genes and used a consensus WGCNA to verify that our conclusions were conservative and reproducible across multiple independent datasets. A total of 5,414 genes were obtained for WGCNA, from which highly correlated genes were divided into 17 modules. The red module demonstrated the highest correlation with the sJIA module (r = 0.8, p = 3e⁻²⁹), whereas the green‐yellow module was found to be closely related to the non‐sJIA module (r = 0.62, p = 1e⁻¹⁴). Functional enrichment analysis demonstrated that the red module was mostly enriched in the activation of immune responses, infection, nucleosomes, and erythrocytes, and the green‐yellow module was mostly enriched in immune responses and inflammation. Additionally, the hub genes in the red module were highly enriched in erythrocyte differentiation, including ALAS2, AHSP, TRIM10, TRIM58, and KLF1. The hub genes from the green‐yellow module were mainly associated with immune responses, as exemplified by the genes KLRB1, KLRF1, CD160, and KIRs. We identified sJIA‐related modules and several hub genes that might be associated with the development of sJIA. Particularly, the modules may help understand the mechanisms of sJIA, and the hub genes may become biomarkers and therapeutic targets of sJIA in the future.

Objective: Clinical and prognostic features of Anti-MDA5-Positive Dermatomyositis (MDA5+ DM) are diverse. This study aimed to examine the peripheral immune cell profiles of patients with MDA5+ DM, identify disease endotypes related to the heterogeneous manifestations and prognosis, and guide individualized therapy regimen.Methods: This inpatient cohort included 123 patients with MDA5+ DM. Unsupervised hierarchical clustering analysis was used to derive disease endotypes from the circulating immune cell profiles on admission. Clinical symptoms, laboratory test results, inpatient treatments, and disease outcomes were then analyzed among the identified endotypes.Results: Three disease endotypes in MDA5+ DM were identified from peripheral immune cell profiles. Endotype1 had the highest percentages of CD4⁺ T cells and monocytes, and the lowest percentage of neutrophils; Endotype2 had the highest percentage of B cells; Endotype3 had the highest percentage of CD8⁺ T cells and NK cells. Clinical and prognostic heterogeneity of the endotypes were revealed. Endotype1 had the lowest 3-month mortality with the high incidence of periungual capillary changes. Endotype2 and Endotype3 had higher prevalence of rapidly progressive interstitial lung disease (RPILD) and mortality at 3 months than Endotype1. Meanwhile, Endotype3 had higher pneumocystis jiroveci and CMV viremia cases with significantly elevated of activated CD8⁺ T cells and multiple cytokines than Endotype1.Conclusion: Clustering analysis of peripheral immune cell profiles identified three different endotypes in MDA5+ dermatomyositis. Endotpye2 and 3 showed higher RPILD, 3-month mortality, pneumocystis jiroveci and CMV viremia.

Macrophage activation syndrome (MAS) represents a severe and potentially life-threatening complication of adult-onset Still’s disease (AOSD), necessitating the identification of sensitive and specific biomarkers for early diagnosis. Our study found significantly elevated CD64 mRNA expression in neutrophils of AOSD patients compared to healthy controls (p = 0.029). The neutrophil CD64 index (nCD64 index) positively correlated with key clinical manifestations, including splenomegaly, sore throat, pulmonary infiltrates, and pericarditis. Effective treatments led to a rapid and significant decrease in the nCD64 index (p < 0.001). Logistic regression showed that an elevated nCD64 index is a risk factor for MAS (OR = 1.073, p = 0.003). ROC curve analysis indicated that the nCD64 index reliably distinguished AOSD patients with MAS (AUC = 0.877; cutoff = 32.09; p < 0.001) and combined utilization of nCD64 index, ferritin, and sIL-2R demonstrated a strong predictive value. Correlations with hospitalization length (r = 0.382, p < 0.001) and maximum glucocorticoid dose (r = 0.326, p = 0.003) were also observed. Kaplan-Meier analysis revealed a significantly higher cumulative incidence of MAS in patients with an nCD64 index > 32.09 (p < 0.001). These findings suggest the nCD64 index is a promising biomarker for early identifying AOSD patients at risk of MAS, aiding in timely diagnosis and management.

Early administration of IL-6R blockade is effective in adult-onset Still’s disease (AOSD), but the underlying immune alterations during combined immunotherapy remain unclear. We employed high-dimensional single-cell mass cytometry and an unbiased bioinformatics pipeline to characterize the immune landscape in treatment-naïve AOSD patients, stable AOSD patients after 24 weeks of IL-6R blockade plus methotrexate and prednisone, and matched healthy controls. Cytokine profiling was conducted using a high-throughput cytometric bead array, and potential regulatory networks were identified using the PerformanceAnalytics package. Validation was performed via flow cytometry and mRNA sequencing. We identified 22 peripheral immune cell populations and characterized their composition and phenotypic markers. Treatment-naïve AOSD patients exhibited significant depletion of CD4+ T cells and B cells, along with excessive activation of CD8+ T cells and a previously unreported CD45+CD3−CD19−CD10−CD66a+ population, findings that were validated in an independent AOSD cohort. mRNA sequencing revealed the proinflammatory role of CD8+ T cells. Notably, these dysregulated immune profiles were markedly restored following immunotherapy. IL-18, IL-21, and IFN-γ demonstrated strong associations with adaptive immune cells and AOSD clinical indices. Combined IL-6R blockade effectively modulates immune dysregulation in refractory AOSD, reversing key pathological immune alterations and highlighting its therapeutic potential.