Genetic associations to germinal centre formation in primary Sjögren's syndrome

Background Primary Sjögren's syndrome (pSS) is an autoimmune rheumatic disease mainly characterised by focal mononuclear cell infiltration in the salivary and lacrimal glands, and by the symptoms xerostomia and keratoconjunctivitis sicca. Germinal centre-like structures (GC) are found in the minor salivary glands of approximately 25% of patients. In this study, we aimed to assess genetic variations in pSS patients with GC-like formations (GC+) compared with patients without such formations (GC−). Methods Minor salivary gland biopsies from Swedish and Norwegian pSS patients (n=320) were evaluated for GC-like formations, identifying 76 GC+ and 244 GC− patients. A panel of 1536 single-nucleotide polymorphisms (SNPs) in 107 genes was genotyped. Minor allele frequencies in GC+ and GC− patients were compared using Fisher's exact test, and associations were considered significant when p