Sjögren's Syndrome and Ankylosing Spondylitis Association: A Case-Based Review.

Introduction: Unlike restrictive pulmonary function and apical fibrobullous disease, diffuse interstitial lung disease is scarce in patients with ankylosing spondylitis (AS). We present a systematic review of the association between AS and SS. We also report a new case of SS revealed by interstitial lung disease in AS patients treated with tumor necrosis factor (TNF) inhibitors.

Materials and methods: The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline using the MEDLINE and SCOPUS databases and included case reports and case series describing the association between AS and SS.

Results: There were sixty-three patients, including our case: 16 males and 47 females. The mean age was 49.2 years. The mean SpA duration was 14.1 years. The mean delay between SpA and SS was 12.8 years (0-27). SS was diagnosed after SpA in 62% of cases (n=39). It preceded SpA in 36.5% (n=23) and was concomitant with SpA in 1 case. All patients had sicca symptoms. MSGB showed focal sialadenitis grade III or grade IV in the Chisholm classification in 20 patients. Anti- nuclear antibody was positive in 75.8% of cases. Among them, anti-SSA and anti-SSB were positive in 44.4% and 35.3% of cases. Except for our patient, no patient had interstitial lung disease. SS extra glandular manifestations were reported in 12 cases.

Conclusion: The occurrence of Sjögren's syndrome is uncommon in patients with ankylosing spondylitis. This association has been reported in the literature, suggesting a pathogenetic link between these two diseases. This association should be considered in ankylosing spondylitis patients with diffuse interstitial lung disease. Knowing this association is necessary for therapeutic adjustment. Our study has some limitations. Publication bias was the major bias in our study. Indeed, we only included case reports and case series describing the association between SpA and SS. We did not search for unpublished work. Moreover, the follow-up was not specified in most included articles.