Hyperactivation and altered selection of B cells in patients with paediatric Sjogren’s syndrome

• DOI: 10.1136/rmdopen-2023-003800
• Publication Date: 2024-03-07T05:55:17Z
• Authors: Alessandra Boni; Rebecca Nicolai; Ivan Caiello; Francesca Marinaro; Luciapia Farina; Denise Pires Marafon; Rita Carsetti; Fabrizio De Bened...; Claudia Bracaglia; Emiliano Marasco
• Keywords: Adult; B-Lymphocytes; Sjögren Syndrome; R; Autoimmune Diseases; 03 medical and health sciences; Sjogren's Syndrome; 0302 clinical medicine; T-Lymphocyte Subsets; Medicine; Humans; Child

ObjectivesPaediatric Sjögren’s syndrome (pSS) is a rare chronic autoimmune disorder, characterised by inflammation of exocrine glands. B cell hyperactivation plays a central role in adult-onset Sjogren. This study was designed to analyse B cell and T cell phenotype, levels of BAFF, and selection of autoreactive B cells in patients with pSS.MethodsA total of 17 patients diagnosed with pSS and 13 healthy donors (controls) comparable for age were enrolled in the study. B cell and T cell subsets and frequency of autoreactive B cells in peripheral blood were analysed by flow cytometry. Levels of BAFF were analysed by ELISA.ResultsThe relative frequency of total B cells, transitional, naïve and switched memory B cells was similar between pSS patients and controls. In patients with pSS, we observed a reduction in the frequency of unswitched memory B cells, an increased frequency of atypical memory B cells and an expansion of PD1hiCXCR5−T peripheral helper cells. Levels of BAFF were higher in patients with pSS compared with controls and correlated with serum levels of total IgG and titres of anti-Ro antibodies. The frequency of autoreactive B cells in the transitional, unswitched memory and plasmablast compartment was significantly higher in pSS patients than in controls.ConclusionsOur results point to a hyperactivation of B cells in pSS. Current therapies do not seem to affect B cell abnormalities, suggesting that novel therapies targeting specifically B cell hyperactivation need to be implemented for paediatric patients.