This study investigates the expression profiles and clinical significance of oxidative stress-related genes (ORGs) and ferroptosis-related genes (FRGs) in peripheral blood mononuclear cells (PBMCs) of patients with ankylosing spondylitis (AS).

GSE73754 datasets were retrieved from the Gene Expression Comprehensive (GEO) database and identified differentially expressed genes (DEGs). FRGs were sourced from the Ferroptosis Database, and ORGs were extracted from the Molecular Signatures Database (MSigDB). These datasets were intersected with DEGs, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Protein-protein interaction (PPI) networks were constructed, and the cytoHubba tool was utilized to identify hub genes. Key genes were derived by intersecting the hub gene sets from the two PPI networks. Immune infiltration analysis was conducted using the single-sample gene set enrichment analysis (ssGSEA) algorithm. Key gene expression levels were validated using RT-qPCR in PBMCs from 113 AS patients (53 active, 60 stable), 48 rheumatoid arthritis (RA) patients, 24 osteoarthritis (OA) patients, and 50 healthy controls. Correlations between gene expression and clinical markers were also analyzed.

 A total of 44 differentially expressed FRGs and 40 differentially expressed ORGs were identified. Enrichment analyses revealed that these genes were primarily associated with oxidative stress, lipid metabolism, and ferroptosis pathways. Seven key genes were identified at the intersection of the two PPI networks: G6PD, CYBB, TXNRD1, AKR1C3, MAP3K5, PARK7, and NFE2L2. G6PD and CYBB were upregulated, while TXNRD1, AKR1C3, MAP3K5, PARK7, and NFE2L2 were downregulated in the PBMCs of AS patients. G6PD expression was significantly elevated in HLA-B27-positive patients and higher in the AS group compared to the OA and RA groups. Additionally, CYBB expression levels positively correlated with AS-related inflammatory markers. The diagnostic potential of G6PD for AS was supported by an area under the curve (AUC) of 0.819 (95% CI: 0.74–0.89, P < 0.001).

 Differentially expressed FRG and ORG play a key role in the pathogenesis of AS, with G6PD and CYBB potentially serving as potential diagnostic biomarkers or therapeutic targets. These findings provide valuable insights into the involvement of ferroptosis and oxidative stress in AS progression.