In a study directly measuring NO in otitis media with effusion, 50 patients with OME were compared in terms of NO, as well as the percentages of CD4+ and CD8+ T lymphocytes, CD4+/CD8+ ratio, IL-2, IL-4, IL-6, and immunoglobulin E (IgE) in peripheral blood and middle ear effusion (MEE) with 50 healthy children as the control group. This evidence concerns the gene CD4 and otitis media with effusion.