Inflammatory arthritis irAE may represent a unique autoimmune disease primarily driven by T cells, but likely not autoantibodies

The underlying immunopathogenesis of inflammatory arthritis (IA) immune-related adverse event (irAE) remains obscure. Unlike rheumatoid arthritis (RA), where autoantibodies and B-cell dysfunction are central features, the contribution of humoral immunity to IA-irAE is unclear. Here, we performed immunophenotyping of peripheral blood from IA-irAE patients and compared them with seronegative RA patients, ICI-treated patients without irAE, and healthy controls. IA-irAE was marked with increased cytotoxic gene expression and metabolic activation in T cells, and reduced CXCR3 and CCR6 expression in CD4⁺ T cells. Contrary to seronegative RA, IA-irAE patients displayed no significant elevation in autoantibody levels or atypical CD11c⁺CD21⁻ B cells. IA-irAE was further characterized by elevated levels of IL-6, IL-12, and type I IFN, which correlated with the T cell activation phenotypes. Altogether, our findings define IA-irAE as a disease with certain immunological features distinctive from RA..., In this study, explicit consent was obtained from all patients, and samples were collected only after patients had provided consent to participate in the study. Meanwhile, we only use the study ID named by our group for all of the patients, thus the data were all de-identified. , , # Data from: Inflammatory arthritis irAE may represent a unique autoimmune disease primarily driven by T cells, but likely not autoantibodies

Dataset DOI: [10.5061/dryad.fxpnvx167](https://doi.org/10.5061/dryad.fxpnvx167)

## Description of the data and file structure

We did single cell sequencing data on 4 groups of patients (HC, RAC, irAE and ICI) using the PBMCs. UMAP, Top 100 TCR clones and top 20 genes of each individual were presented. We also included gene maker of each cluster and cell counts in each cell type.

### Files and variables

#### File: Auxiliary_Data_3_heatmap_from_scRNAseq_analysis.jpg

**Description:** Gene expression heatmap from scRNAseq analysis for each cell type.

#### File: Auxiliary_Data_1_Individual_UMAP.tiff

**Description:** Individual UMPA for each patient

#### File: Auxiliary_Data_2_Individual_Top_100_clones.tif

**Description:** Top 100 TCR clones distribution in T cells

#### File: Auxillary_Table_2_cell_counts_patient.csv

**Description:** Cell co...,