Relationship of T lymphocytes, cytokines, immunoglobulin E and nitric oxide with otitis media with effusion in children and their clinical significances. OBJECTIVE: To investigate the relations of T lymphocytes, cytokines, immunoglobulin E, and nitric oxide with otitis media with effusion (OME) in children and their clinical significances. METHODS: Fifty children with OME treated in our hospital were enrolled in the study (observation group). Fifty healthy children were selected as control. The percentages of CD4+ and CD8+ T lymphocyte and CD4+/CD8+ ratio in peripheral blood, and the levels of cytokine (IL)-2, IL-4, IL-6, immunoglobulin E (IgE) and nitric oxide (NO) in peripheral blood and middle ear effusion (MEE) in both groups were detected. The correlations of these indexes with OME were analyzed. RESULTS: The percentage of peripheral blood CD4+ and CD8+ levels, CD4+/CD8 ratio, IgE, and NO levels in the observation group were significantly higher than those in the control group (P < 0.01). In the observation group, the IL-2 and IL-6 levels, and IgE and NO levels in the MEE were significantly higher than those in peripheral blood (P < 0.01). In addition, in the observation group, the MEE IL-2 and IL-6 levels were positively correlated with peripheral blood CD4+/CD8+ ratio, respectively r = 0.366, P = 0.009; r = 0.334, P = 0.018. CONCLUSIONS: The levels of peripheral blood CD4+ and CD8+ lymphocytes and MEE IL-2, IL-6, IgE, and NO levels are increased in children with OME. These indexes have provided significant clues for the diagnosis of OME in children.