Yeast that live in the human gut can trigger the immune system to cause inflammation in the lung, especially in patients with ABPA.

The yeast Candida albicans lives in the gut as a commensal organism, usually without issue. C. albicans causes the body to produce a particular kind of immune cell, called Th17 sensitive cells, that stop the Candida from causing infections. A new research paper out this month shows that the Th17 cells that react to Candida in the gut also react to Aspergillus in the lung by a process called ‘cross reactivity’.

Cross reactivity was shown to increase the levels of Aspergillus reactive Th17 cells in the blood of patients with Cystic Fibrosis, COPD and asthma, especially during ABPA. This indicates that there is a direct link between the normal, protective Th17 responses against Candida in the gut, and harmful inflammation by Aspergillus in the lung.

In other words, problems in your lungs might be made worse by the normal immune response to Candida in your gut. This knowledge could affect the way we treat flare ups in future. For example, we already know that using antibiotics can increase the growth of Candida in the gut. This new information raises the possibility that increased Candida in the gut could cause increased lung inflammation or a ‘flare up’ of symptoms in patients with Aspergillosis, but further work would be needed to confirm this.

Read the paper here