Non-negligible prevalence of focal lymphocytic sialadenitis in minor salivary glands of non-Sjögren's disease individuals.

Objectives: Focal lymphocytic sialadenitis (FLS) in minor salivary gland biopsy (MSGB) has long been regarded as a histologic hallmark of Sjögren's disease (SjD), but it can also occur in non-SjD individuals. This study aimed to define the prevalence of FLS in labial minor salivary glands of non-SjD individuals via both an autopsy study and a meta-analysis.

Methods: A total of 214 genotype-tissue expression (GTEx) volunteers was included in the autopsy study, and FLS in labial minor salivary gland was evaluated. A meta-analysis was also performed to comprehensively define the prevalence of FLS in labial minor salivary glands of non-SjD individuals.

Results: In the autopsy study of 214 GTEx volunteers, the frequency of FLS in labial minor salivary glands was 13.1%. GTEx volunteers aged 60 years and older demonstrated a greater prevalence of FLS compared to those volunteers younger than 60 years (20.3% vs. 9.7%, p=0.03). In the meta-analysis, a total of 8 eligible studies involving 917 labial minor salivary gland samples were included. The pooled prevalence of FLS in labial minor salivary glands of non-SjD individuals was 6.2%. In the subgroup analysis by gender, the pooled prevalence of FLS in labial minor salivary glands for female and male non-SjD individuals was 10.4% and 5.0%, respectively.

Conclusions: This study provides compelling epidemiological evidence for the considerably high prevalence of FLS in minor salivary glands of non-SjD individuals. The clinical significance of FLS should be cautiously considered when MSGB is used to confirm seronegative SjD.