Background: Atlanto-axial joint (AAJ) involvement is a severe complication in rheumatoid arthritis (RA) that can pose a life-threatening risk. The immunological profile of patients has significant diagnostic and prognostic value in RA. The objective of our study was to investigate the potential link between atlanto-axial dislocation (AAD) and the immunological status of RA patients.

Objectives: The objective of our study was to investigate the potential link between atlanto-axial dislocation (AAD) and the immunological status of RA patients.

Methods: This was a cross-sectional case-control study involving 449 RA patients (diagnosed according to ACR/EULAR 2010 criteria) followed in the Rheumatology Department of Hassan II University Hospital between January 2014 and March 2024. AAD was defined as an anterior atlanto-axial distance (AADI) ≥ 4 mm on cervical spine radiographs in hyperflexion and/or evidence of anterior, posterior, lateral, or rotatory dislocation at C1C2 on MRI, with or without inflammatory signals. Statistical significance was set at p < 0.05. The immunological profile was assessed based on the positivity and levels of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA), with high positivity defined as levels exceeding three times the normal range.

Results: A total of 449 patients were included, with a mean age of 57.7 ± 12.4 years and a female-to-male ratio of 5.5:1. The mean disease duration was 14 ± 7.6 years. AAD was observed in 12 patients (2.7%). Patients were divided into two groups:

• Group 0 (G0 ): Patients without AAD (n = 436).

• Group 1 (G1 ): Patients with AAD (n = 12).

In G1 (11 women, 1 man), the mean age was 51.6 ± 17 years, with a mean disease onset age of 35.3 ± 13.5 years and a median disease duration of 16 ± 11 years. RA was seropositive and erosive in 81.9% and 75% of cases, respectively. RF was positive in 72.8% of cases, while ACPA (tested in 10 patients) was positive in 70%. High levels of RF and ACPA were observed in 58.3% and 50% of cases, respectively. In G0, the mean age was 57.8 ± 12.3 years, the mean disease onset age was 44 ± 13 years, and the median disease duration was 14 ± 8 years. RA was seropositive and erosive in 79.1% and 64.3% of cases, respectively. RF and ACPA (tested in 381 patients) were positive in 86.4% and 64.6% of cases, with high levels in 68.4% and 53% of cases, respectively. Bivariate analysis showed no significant association between the immunological profile and AAD occurrence in RA patients.

Conclusion: Despite its prognostic importance, the immunological profile was not associated with atlanto-axial joint involvement in our study. Further large-scale studies are required to confirm these findings.

REFERENCES: [1] Smolen, J. S., Aletaha, D. & McInnes, I. B. Rheumatoid arthritis. Lancet 388 , 2023–2038 (2016).

[2] Shlobin, N. A. & Dahdaleh, N. S. Cervical spine manifestations of rheumatoid arthritis: A review. Neurosurg. Rev. 44 , 1957–1965 (2021).

Acknowledgements: NIL.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.