Though usually tasked with protecting us, an overactive immune system that does its job too well can create problems of its own. One example is atopic dermatitis, a common form of eczema characterized by itchy rashes and dry skin. Although one in five people around the world will suffer from atopic dermatitis, some people seem to experience more severe itching, which complicates treatment.
It was suspected that the microbiome might have a role to play in the varying severity of the disease, and now, researchers led by John Common, a Principal Investigator at Skin Research Institute of Singapore (SRIS), have discovered different skin microbiome signatures that may suggest why.
“Our findings provide the first evidence that intrinsic skin microbiome states can be used for stratification and prognostication in a common skin disease,” said Common, who is a co-corresponding author on the study.
Looking at the microbial signatures of National Skin Centre patients, the researchers were able to get a picture of what the microbiome of someone with severe atopic dermatitis looks like. They identified two microbiome states, which they termed Dermotypes A and B, that are linked to different disease outcomes.
Dermotype B, the dermotype associated with more severe itching and frequent flares, shows reduced microbial richness, altered metabolic capacity and enrichment of virulence genes on the skin. This altered microbial ecology could be a mechanism for driving the ongoing systemic inflammation that is seen in atopic dermatitis.
“Interestingly, when we integrated our data on the skin microbiome, host immunity and skin barrier function, we show that the dermotypes provide a link to a mechanism for microbiome-driven inflammation and increased disease severity,” co-corresponding author Niranjan Nagarajan said.
These dermotype signatures could provide unique insights into altered skin ecology that facilitates microbial virulence, Common said. Also, they could help researchers understand the early life events that shape a healthy microbiome and serve as a basis for more effective treatments tailored for severity.
“The ability to manipulate the skin microbiome has great promise for treating skin diseases," said Common. “It raises the possibility that alteration of one’s dermotype state could reduce disease susceptibility and improve barrier function.”
The A*STAR-affiliated researchers contributing to this research are from the Skin Research Institute of Singapore (SRIS), the Genome Institute of Singapore (GIS), the Biological Resource Centre (BRC), and the Singapore Immunology Network (SIgN).
