Incidence of Systemic Vasculitis and Clinical Outcomes in Systemic Sclerosis: 2-Years Follow-Up of Asymptomatic Positive for Anti-Neutrophilic Cytoplasmic Antibody

Abstract

Purpose

Anti-neutrophilic cytoplasmic antibody (ANCA)-associated vasculitis (AAV) overlap with systemic sclerosis (SSc) is uncommon. We aimed to determine the incidence of AAV and define clinical outcomes relevant to asymptomatic screening positive for ANCA in SSc after 2 years of follow-up.

Patients and Methods

The study was a cohort study of 185 Thai adult SSc patients testing for ANCA and having a 2-year follow-up at the Scleroderma Clinic, Khon Kaen University, Thailand. The incidence of AAV and outcomes of those who tested positive for ANCA were evaluated.

Results

A total of 185 SSc patients were tested for ANCA, of whom 21.6% were positive for either cytoplasmic ANCA, perinuclear ANCA (p-ANCA), anti-myeloperoxidase (anti-MPO), or anti-proteinase3 antibody. Only one 52-year-old female patient with dcSSc, negative for initial ANCA test, developed AAV (microscopic polyangiitis) 7 months after the first ANCA test for an incidence of AAV of 0.27 per 100-person-years (95% CI 0.01–1.5). She was positive for p-ANCA and anti-MPO. Eight of those who had an initial test were positive for ANCA and underwent a repeated test. Only two cases persisted as positive for ANCA (1 anti-MPO and 1 anti-PR3) and had no clinicals suspicious of vasculitis. Four cases that had ANCA turned to a negative result.

Conclusion

AAV is a rare complication in SSc, so ANCA may not have any role as a screening test for AAV as it cannot predict the development of AAV in SSc. We suggest testing for ANCA only in SSc patients with clinicals suspicious of AAV.

Keywords:

• systemic sclerosis
• scleroderma
• anti-neutrophilic cytoplasmic antibody
• ANCA- associated vasculitis
• vasculitis

Data Available Statement

Data and material are available from the corresponding author on reasonable request.

Ethics Approval and Consent to Participate

The Human Research Ethics Committee of Khon Kaen University reviewed and approved the study as per the Helsinki Declaration and the Good Clinical Practice Guidelines (HE631305). The Human Research Ethics Committee of Khon Kaen University waived the requirement for informed consent because of the retrospective nature of the study. Participant privacy was protected by anonymized data and maintained confidentiality. The study methods were performed in accordance with the Helsinki Declaration statement.

Consent for Publication

The authors consent to publication and grant the Publisher exclusive license of the full copyright.

Acknowledgments

The authors thank (a) the Scleroderma Research Group, Khon Kaen University for support, and (b) Mr. Bryan Roderick Hamman under the aegis of the Publication Clinic Khon Kaen University, Thailand, for assistance with the English-language presentation. The abstract of this paper was presented at the 23rd Asia-Pacific League of Associations for Rheumatology (APLAR) Congress as a poster presentation with interim findings. The poster’s abstract was published in ‘Poster Abstracts’ in Int J Rheum Dis. 2021;24(Suppl. 2):121–333. DOI: 10.1111/1756-185X.14200.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

The study received funding support from the Research and Graduate Studies, Khon Kaen University, Thailand.