TLR4 and asthma: Our present findings showing higher numbers of induced sputum macrophages expressing TLR4 in asthmatic subjects with high total serum IgE, along with a correlation (weak) between the percentage of TLR4+ macrophages and the total serum IgE level, are consistent with the idea of a relationship between respiratory exposure to PAMPs and asthma with increased IgE, and suggest an involvement of the macrophage in such relationship.