Prevalence and outcomes of atrial fibrillation in hospitalizations during pregnancy and puerperium.

Relapsing polychondritis (RP) is a rare immune-mediated systemic disease that has a predilection for causing damage to cartilaginous tissue or tissue rich in proteoglycans (). Respiratory involvement in RP, which primarily affects the larynx, trachea, and bronchi, is not only a common complication but also a major cause of mortality (, ). Patients with respiratory involvement often present with symptoms such as cough, wheezing, and dyspnea. These symptoms progressively worsen as immune-mediated inflammation causes cartilage destruction, leading to airway malacia, collapse, or even obstruction (, ). The diagnosis of RP with initial respiratory involvement, especially at an early stage, remains a major clinical challenge. Because the clinical manifestations are highly similar to those of common chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD), this frequently results in misdiagnosis or delayed diagnosis (). Therefore, analyzing the clinical feature spectrum of RP patients with respiratory involvement is of great clinical significance. To date, the pathogenesis of RP remains largely unknown. A small body of evidence suggests that exposure to autoantigens, such as type II collagen and matrilin-1, which are specific to cartilaginous tissues (), and to misfolded proteins may play pivotal roles in initiating the autoimmune response, leading to inflammation and subsequent cartilage damage (). Notably, respiratory involvement in RP, which occurs in approximately half of patients and can lead to life-threatening complications (), has a poorly understood underlying pathogenesis. Proteomics has emerged as a powerful tool in unraveling the complex molecular mechanisms of autoimmune and inflammatory diseases (). It enables high-throughput detection and analysis of global protein expression profiles, facilitating the identification of novel biomarkers and pathogenic molecules. This study retrospectively analyzes the clinical features of RP patients with respiratory involvement, aiming to improve their identification. Additionally, this study aims to explore the protein expression profiles of patients with respiratory-involved RP using proteomic approaches, thus elucidating the underlying pathogenesis of this subset of patients.