Second immunoglobulin-binding protein (Sbi) is a unique trigger of eczema by Staphylococcus aureus, according to research in the Journal of Allergy and Clinical Immunology.

Sbi induces rapid release of Interleukin-33, a key component of the immune response in childhood eczema, the study authors note.

“Our study shows beyond any doubt that Sbi is the dominant infective trigger of eczema and that is incredibly exciting,” says Peter Arkwright, a senior Lecturer and honorary consultantat the University of Manchester in Manchester, UK and a Consultant in Paediatric Allergy & Immunology at Royal Manchester Children’s Hospital,  part of Manchester NHS Foundation Trust, in a news release. “Scientists have long known that Staphylococcus aureus is the dominant pathogen on human skin, causing the majority of skin and soft tissue infections worldwide, but only now do we understand that it is only because it expresses predominant virulence factor Sbi, that allergic eczema is triggered.”

The search for this missing link involved mouse eczema model studies led by Tokyo University of Agriculture and Technology and bench work on cells and human skin tissue at Manchester. The scientists also studied six other species of staphylococci, as well as the common Group A strep which causes tonsillitis and scarlet fever, but none generated allergic responses.

In each part of the study, the results pointed to Sbi - first discovered in 1998 - as the trigger.

 “Our primary aim was to understand why Staphylococcus aureus is so uniquely associated with allergic reactions in skin,” says study co-author Joanne Pennock, a Senior Lecturer in the Division of Infection, Immunity & Respiratory Medicine at the University of Manchester. “The precise mechanism that drives the allergic pathology in eczema patients has been a mystery, until now. Staphylococcus aureus expresses many virulence factors so finding the right protein was a challenge. We have shown that only golden Staph that expresses Sbi is capable of causing the allergic skin response.”

Now the aim is to learn more about Sbi to lay the groundwork for future non-steroid treatments, she notes.