6. Anti-Collagen II Antibodies in Patients with Relapsing Polychondritis
Creators: name: Ferrada, Marcela
name: Quinn, Kaitlin
name: Yiminng Luo
name: Ms Kristina Wells
name: Sikora, Keith
name: Goodspeed, Wendy
name: Grayson, Peter
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background: </strong>Relapsing polychondritis (RP) is a heterogenous systemic inflammatory disease that affects multiple organ systems, in particular, cartilaginous structures. Clinical presentations in RP are variable, making recognition and diagnosis of the disease challenging. Testing for anti-collagen II (CII) antibodies have been proposed as a diagnostic tool t RP; however, the data remains inconclusive as to what percentage of RP patients have anti-CII antibodies and the value for diagnosis. Our objectives were to evaluate the utility of anti-CII antibody as a diagnostic tool in patients with RP. <strong>Methods:</strong> Patients 18 years and older were recruited into a prospective observational cohort of RP. Diagnosis of RP was made using McAdams or Damiani’s diagnostic criteria for RP. All patients referred for evaluation of RP with anti-CII antibodies measured were included. Patients with VEXAS syndrome were excluded. Anti-Cll antibodies were assayed via a clinically certified ELISA test (Mayo Clinic, Rochester, MN) in all patients evaluated from July 2019 to October 2021. Clinical features were compared between patients with a diagnosis of RP stratified by presence of anti-CII antibody results using Fisher’s exact test or Wilcoxon rank sum test as appropriate. <strong>Results:</strong> 60 patients were tested for anti-CII antibodies, from those nine patients (15%) had elevated levels. Two patients did not meet diagnostic criteria for RP and, from those, one patient had elevated anti-CII antibodies. 58 patients met diagnostic criteria for RP and were included on further analysis. Seven patients (12%) had repeated measurements. One patient had an initial positive anti-CII, with a follow up negative value. Six patients (10%) had an initial negative anti-CII, with all of the repeat values remaining negative except for one patient. Patients with a diagnosis of RP with elevated anti-CII antibodies compared to those without elevated antibodies have significantly higher prevalence of genital ulcers (38% vs 8%, p = 0.01), sicca symptoms (88 vs 38%, p = 0.01) and a diagnosis of MAGIC ((mouth and genital ulcers with inflamed cartilage) syndrome (38% vs 8%, p=0.01). There were no statistical differences between the groups for age of disease onset, sex, other clinical manifestations, elevated inflammatory markers, treatment, organ damage, ICU admissions or death. <strong>Conclusion:</strong> Anti-CII antibodies have a limited role as a diagnostic test and biomarker of disease activity in RP. Presence of anti-CII antibodies may be associated with specific clinical symptoms and may be enriched in a subset of patients with RP who have mucocutaneous disease. This subset is commonly referred to as MAGIC syndrome. Whether anti-CII antibodies provide pathogenic insight for a smaller subset of patients with RP remains to be determined. <strong>Disclosures:</strong> None