TLR4 and pneumonia: Chalk et al recently found that patients who developed pneumonia post‐operatively had decreased TLR4 expression in alveolar macrophages, suggesting that local cell‐mediated immunosuppression might be a risk factor for post‐operative pneumonia.30 TLR4 expression in alveolar macrophages in acute respiratory distress syndrome (ARDS) is suppressed, even after ex vivo stimulation to LPS.30