Genes involved in antigen presentation (RT1-Ba, RT1-Da, RT1-Bb, RT1-DMb, RT1-M3-1, RT1-Db1, CD74), immune, defense, inflammation (RatNP-3, Lyz2, Pla2g2a), and components of the extracellular matrix (Col1a1, Fn1, Col3a1) were among those most highly induced by AOM-treatment (Table 2). The gene discussed is PLA2G2A; the disease is infectious otitis media.