In nongonococcal urethritis caused by Chlamydia trachomatis, the urethral discharge predominantly contains neutrophils. This is because neutrophils are the primary cells involved in the acute inflammatory response to bacterial infections, including intracellular bacteria like Chlamydia. They act as first responders, migrating to the site of infection to phagocytose pathogens and release enzymes to control infection. Eosinophils and basophils are more involved in allergic or parasitic conditions, while lymphocytes are key in chronic inflammation and viral infections. Therefore, the presence of neutrophils in urethral discharge indicates an acute bacterial inflammatory process typical of chlamydial urethritis.

Reference: Robinson’s Current Therapy in Infectious Diseases, Bennett JE, 8th Edition.