Aspergillus positivity in young children with CF is not associated with bronchiectasis
medwireNews: In 5-year-old children with cystic fibrosis (CF), positivity for Aspergillus species in bronchoalveolar lavage (BAL) cultures is associated with air trapping but not with bronchiectasis or reduced lung function, indicates a longitudinal study.
“It is possible that Aspergillus may either have a direct role in early lung injury, manifested by air trapping, or act as a marker for other pathological events, which ultimately lead to irreversible structural airway wall damage and bronchiectasis,” suggests the research team.
At 5 years of age, 28 (17.9%) of 156 children participating in the Australasian Cystic Fibrosis Bronchoalveolar Lavage (ACFBAL) study had positive BAL cultures for Aspergillus. And these children, compared with those testing negative for Aspergillus, had a significant 5.53-fold increased probability of air trapping on high-resolution computed tomography after taking into account prior intravenous, inhaled and oral antibiotic exposure and interleukin-8 values of at least 250 ng/mL.
By contrast, the presence of Aspergillus did not affect the children’s probability of having bronchiectasis.
The children with air trapping at the age of 5 years had an average predicted reduction in forced expiratory volume in 1 second (FEV1%) at baseline of 4.17, compared with those without air trapping, but the researchers found no association between Aspergillus-positive BAL cultures and FEV1% predicted at this age.
There was also no association between Aspergillus positivity and FEV1% predicted measured between the ages of 5 and 14 years in a longitudinal analysis of 79 ACFBAL children who were recruited into a subsequent study and had data recorded in the Australian CF data registry.
“Nutritional status and hospitalisation secondary to pulmonary exacerbations were found to be the major factors adversely affecting lung function in young patients with CF rather than the presence of Aspergillus”, write Sabariah Noor Harun (Universiti Sains Malaysia) and co-researchers in Thorax.
The major Aspergillus species identified among 5-year-olds was A. fumigatus (16.0% of 156 children), followed by A. terreus (1.3% of 156 children) and A. niger (0.64% of 156 children).
Being an observational study, causation could not be determined, say Harun and colleagues, and they acknowledge that “whether Aspergillus is a cause or a marker for worse lung disease is difficult to determine as risk factors for Aspergillus are also associated with worse outcomes in CF.”
The researchers therefore conclude that “this can only be resolved by a randomised controlled trial of anti-fungal therapy to eradicate Aspergillus in children with CF and then to determine if this provides a measurable clinical benefit.”
By Catherine Booth
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