People with allergies have different things living in their noses

By Stephen Beech via SWNS

People whose allergies cause the "sniffles" have different fungi living in their noses, reveals new research.

Scientists examining the noses of patients with asthma and allergic rhinitis found that their nasal fungi were different to those of healthy people.

They say their findings, published in the journal Frontiers in Microbiology, indicate future targets for treatment.

Around one in four adults have allergies that cause a runny nose.

The respiratory disease, formally called allergic rhinitis and frequently associated with asthma, is a common problem around the world.

The upper airway is a key target for research into the underlying disease processes.

Now an international team of researchers has discovered that patients with allergy-induced sniffles and asthma have different fungal colonies - known as "mycobiomes" - in their noses.

Study co-author Dr. Luís Delgado, of the University of Porto in Portugal, said: “We showed that allergic rhinitis samples displayed a significantly higher fungal diversity and a different fungal community structure compared to those of healthy controls.

“This may suggest that allergic rhinitis increases the diversity and changes the composition of the upper airway’s microbiome.”

Dr. Delgado explained that allergic rhinitis causes sneezing, itching, inflamed nasal mucous membranes, and a blocked and runny nose.

He said that it’s often linked with asthma, which also involves inflammation and obstructed airways.

The research team says allergic rhinitis and asthma may even be different aspects of the same airway inflammatory disease, which makes it critical to identify the links between them and the underlying causes.

To study the nasal mycobiome, the team recruited 214 participants from among children and young adults attending an immunology and asthma clinic in Porto.

A total of 155 patients had both allergic rhinitis and asthma, while 47 were only diagnosed with allergic rhinitis and 12 with asthma. The team also recruited 125 healthy people.

Researchers took samples from the participants’ noses using nasal swabs and sequenced the fungal DNA they found, focusing on two specific regions to identify different fungal species and develop an overview of each participant’s mycobiome.

The team used network analysis to understand the relationships between different genera of fungi and to characterize the different communities of fungi present in healthy and sick study participants.

They also investigated the function of different fungi, looking at the metabolic pathways they affect, to try to understand the implications of any mycobiome variation between the groups of patients.

The most common families of fungi across all samples were Ascomycota and Basidiomycota. In these two families, 14 genera dominated the mycobiomes.

Dr. Delgado said: “Among these dominant genera we detected common fungi that have been recognized in humans as allergenic or opportunistic pathogenic fungi.

“This suggests that the nasal cavity is a major reservoir for fungi that could be involved in allergic rhinitis and asthma.”

He said there was a very clear and statistically "significant" difference between the patients with respiratory diseases and the healthy controls – and no significant difference between the different groups of patients with respiratory diseases.

The findings also showed that patients with respiratory diseases had more diverse and richer mycobiomes.

The fungi sampled from patients with both allergic rhinitis and asthma also showed more evidence of connections between them than the fungi in the healthy participants’ noses and those who only had allergic rhinitis.

That could indicate that the fungi are affecting the nose’s immune environment, according to the research team.

They also found that three metabolic pathways associated with the production of a building block for DNA and RNA - 5-aminoimidazole ribonucleotide or AIR - were "overabundant" in the mycobiome of patients with allergic rhinitis and asthma.

The team said AIR is linked to purine production, which is necessary for energy metabolism and DNA synthesis.

They believe If further studies confirm the link and identify the exact problem, AIR could be a future therapeutic target for treatment or diagnosis.

However, Dr. Delgado cautioned that the team could not control all patient-specific variables - such as disease severity and related treatment levels - and that patients were sampled at a single time.

He explained that the study’s design gives a broad picture, but doesn’t show how the mycobiome changes over time.

Dr. Delgado added: “Addressing some of these clinical variables would be interesting follow-ups of our study if we could get the appropriate funding."