Steroids increase vulnerability to lung infection

Personalised respiratory medicine

New Southampton research explains how steroid treatment increases lung infection risks for chronic obstructive pulmonary disease (COPD) patients, adding to evidence for avoiding high doses.

New research by the NIHR Southampton Respiratory Biomedical Research Unit explains why steroid treatment for the lung condition COPD leads to an increased risk of pneumonia.

Published in the American Journal of Respiratory and Critical Care Medicine, this work adds to evidence supporting the use of lower doses of inhaled steroids for COPD patients.

Impaired immune system

COPD is a chronic lung condition, caused predominantly by smoking, involving chronic breathing difficulties, coughing and wheezing, and affecting around 3 million people in the UK.

Lung infections often cause worsening of symptoms, or ‘exacerbation’ events, requiring a course of steroids to manage this and enable recovery.

However, while inhaled steroids can improve symptoms and reduce exacerbations, their link with increased risk of secondary infection with pneumonia is well established.

This latest research reveals why this is so for the first time. It shows that high doses of steroids impair a specific part of the immune system needed to fight the bacteriathat most commonly cause lung infections and pneumonia in COPD patients.

Refining COPD treatment

The researchers compared the response of a specific type of immune cell, known as MAIT cells, to infection by the pneumonia-causing bacteria H. Influenzae in COPD patients either receiving steroid treatment or not.

They found that those patients who had taken steroids had fewer MAIT cells, and that these cells were less effective at fighting off the bacteria.

The results indicate that COPD patients could benefit from lower doses of steroids, where possible, in order to help prevent secondary lung infections and pneumonia.

Posted on Tuesday 13 December 2016