BackgroundTo explore the relationship among ocular surface changes, systemic hematologic indexes, and disease activity in primary Sj & ouml;gren's syndrome patients.MethodsThirty-three primary Sj & ouml;gren's syndrome patients and 36 healthy controls were recruited in this cross-sectional study. All participants underwent complete ocular surface testing, including dry eye symptoms and signs, tear multi-cytokine analysis, and conjunctival impression cytology (CIC). Multiple systemic hematologic indexes and disease activity were also evaluated, including autoantibodies, immune cells, the EULAR Sj & ouml;gren's Syndrome Patient Reported Index (ESSPRI), and the EULAR Sj & ouml;gren's Syndrome Disease Activity Index (ESSDAI).ResultsPrimary Sj & ouml;gren's syndrome patients exhibited significant dry eye, severe conjunctivochalasis, decreased goblet cell density, and severe squamous epithelial on the ocular surface. Interferon-inducible T cell alpha chemoattractant (I-TAC), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1 beta, IL-5, IL-8, IL-10, IL-13, IL-21, C-C motif chemokine ligand (CCL)4, interferon-gamma (IFN-gamma), CCL20, and tumor necrosis factor-gamma (TNF-alpha) in the tear fluid of pSS patients changed significantly. Correlation analysis showed that anti-SSA was relevant to ocular surface disease index (OSDI) score, tear break-up time (TBUT), and meibomian gland secretion (MGS). CD8+ T cell percentages were relevant to TBUT and corneal fluorescein staining score (CFS). IL-8, IL-13, CCL4, and TNF-alpha were correlated with RF-IgA. IL-1 beta, CCL4, and TNF-alpha were correlated with CD8+ T cell counts. IL-5 and CCL20 were correlated with the ratio of helper T cells and suppressor T cells. Tear I-TAC, IL-8, CCL20, and TNF-alpha were significantly correlated with the ESSDAI of different domains.ConclusionsOur results revealed that the ocular surface changes in pSS patients were significantly correlated with systemic hematologic indexes and disease activity.