The intestinal microbiota and allergic asthma.

There is increasing evidence that environmental changes are involved in the sharp increase in asthma incidence, as well as with other immune-mediated diseases. This increase matches the introduction of modern life advances such as antibiotics and caesarean sections. Several epidemiological studies provide convincing evidence that a lack of exposure to microbes early in life is associated with later development of allergic asthma. In addition, animal studies have shown that early life modulation of the intestinal microbiota with antibiotics has profound effects in the immune cellular mechanisms that lead to asthma. By describing some of the most relevant human and animal studies in this field, we explore the concept that significant perturbations of the intestinal and perhaps the lung microbiota are a cause of allergic asthma.