Immunohistochemical detection of IL-17 and IL-23 improves the identification of patients with a possible diagnosis of Sjogren's syndrome

Objectives: The diagnosis of primary Sjogren’s syndrome (pSS) continues to be difficult and several patients keep symptomatic for years with different diagnoses before confirmation of pSS. Since the IL-23-IL-17 axis is involved in the etiopathogenesis of pSS we evaluated by immunohistochemistry and morphometric methods the presence of IL-17 as well as IL-23 within minor salivary glands (MSG) obtained from patients with uncertain diagnosis of pSS. Materials and Methods: 42 patients, with symptoms attributable to pSS, and 8 patients used as a control, were enrolled for the study. Autoantibody detection, histological analysis for the presence of Germinal Centers (GC+), immunohistochemistry to detect IL-23 and IL-17 were performed. Results: The detection of GC + anti-SSA and anti-SSB antibody in parallel with the detection of IL-17 and IL-23, displays only a diagnostic reinforcement value. Instead, the detection of a positive reaction for both IL-17 and IL23 without GC + or autoantibody within minor salivary glands, as detected in 36 % of patients with uncertain diagnosis, may be hold as a sensitive and specific marker to identify those patients who are likely to evolve into pSS. Conclusion: we suggest to use the IL-17/ IL-23 immunohistochemical detection to improve the identification of patients with a possible diagnosis in all cases which do not fully meet the American-European criteria for pSS, in particular when the GC + are not present at histopathological analysis and anti-SSA and anti-SSB antibody are undetectable in the serum.