Objective:

To evaluate the clinical course of a Polish cohort of SLE patients with ANCA positivity, assessing clinical manifestations, laboratory findings, immunosuppressive treatment strategies, and patient outcomes, including a comparative analysis of patients with anti-MPO and anti-PR3 antibodies.

Approach:

• Study Population: Retrospective analysis of medical records of SLE patients at the University Hospital in Kraków, Poland, from 2012 to 2022, including only those fulfilling the 2019 EULAR/ACR classification criteria.
• Data Collection: Demographic characteristics, clinical manifestations, laboratory data, therapeutic approaches, and outcomes were collected, including ANCA positivity confirmed by ELISA.
• Ethical Approval: Ethical approval was granted by the Bioethics Committee of Jagiellonian University Medical College.

Key Findings:

• ANCA positivity in SLE patients is associated with severe disease manifestations.
• Overlap between SLE and AAV is linked to a high mortality rate.
• Clinical manifestations evaluated included cutaneous involvement, arthritis, and organ-specific complications.
• Comparative analysis revealed differences in clinical presentation and prognosis between anti-MPO and anti-PR3 positive patients.

Interpretation:

The study provides insights into the complexity of SLE with ANCA positivity and the monitoring of clinical manifestations and treatment outcomes.

Limitations:

• Retrospective design may limit the ability to establish causality.
• Single-center study may affect the generalizability of findings.

Conclusion:

The study provides insights into the clinical characteristics and outcomes of SLE patients with ANCA positivity.