Levels of proinflammatory cytokines, interleukin (IL)-1β, IL-6, interferon (IFN)-γ and tumour necrosis factor (TNF)-α in lung homogenates of ovalbumin (OVA)-treated versus control mice with pneumococcal pneumonia. Data are presented as mean ± standard error (pg/ml). The mean levels were significantly lower in the OVA-treated mice with pneumococcal pneumonia than the control mice with pneumococcal pneumonia (P < 0·05). OVA+/infection-, OVA-sensitized/challenged mice without pneumococcal pneumonia; OVA-/infection-, non-sensitized/challenged mice without pneumococcal pneumonia; OVA+/infection+, OVA-sensitized/challenged mice with pneumococcal pneumonia; OVA-/infection+, non-sensitized/challenged mice with pneumococcal pneumonia.