Elevated IL-8 and abnormal Lymphocytes in pediatric primary Sjögren's syndrome: A single-center study

Abstract Background: Cytokines and lymphocytes orchestrating the pathophysiological landscape have been well explored in adults but are rare in children with Sjögren's syndrome. We aimed to assess their potential as biomarkers in pediatric Sjögren's syndrome. Methods: We reviewed 14 pediatric patients with primary Sjögren's syndrome (pSS) who attended a specialized rheumatology clinic over 2 years. A literature review of databases using MeSH headings and keywords for "Sjögren syndrome" and "pediatric." We measured the expression of cytokines: IL-4, IL-5, TNF-α, IFN-γ, TNF-β, IL-6, IL-1β, IL-2, IL-10, IL-8, IL-22, IL-12p70, IL-17F, and IL-17A in the plasma, and the percentages and absolute counts of CD3+, CD19+, CD3-CD16 + and/or CD56+, CD3 + CD4+, CD3 + CD8 + in peripheral blood, from14pSS patients and 12 healthy children. Results: A comparison of cytokines between patients with pSS and healthy children showed higher levels of IL-8 in the patients with pSS. A comparison of lymphocyte biomarkers between pSS patients and healthy children showed higher levels of CD3 + CD8 + lymphocytes in pSS patients, while markers such as CD3+, CD3 + CD4+, CD19+, and CD3-CD16 + or CD3-CD56 + were lower. Conclusions: IL-8 acts as a biomarker in pediatric pSS and might work with the abnormality of T cells, B cells, and NK cells to induce pSS.