ADA and infectious otitis media: As illustrated in Figure 4, exposure to AOM resulted in elevated levels of several enzymes: adenosine deaminase (ADA) increased to 4.13 μm ± 0.14 SEM, gamma-glutamyl transferase (GGT) to 2.5 μm ± 0.11 SEM, ecto-5′-nucleotidase (CD73) to 3.46 μm ± 0.15 SEM, and lactate dehydrogenase (LDH) to 3.13 μm ± 0.14 SEM.