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Asthma is a chronic inflammatory disease driven by the interplay of genetics, environmental factors and a diverse cast of immune cells. Researchers at La Jolla Institute for Allergy and Immunology (LJI) identified a subset of T cells, whose frequency serves as early childhood immune signature that predicts the risk of developing asthma later on.
Children who, at the age of one, had a higher frequency of MAIT cells appear to be less likely to develop asthma by the age of seven. Consistent with the “hygiene hypothesis,” which holds that increased microbial exposure in the first years of life is protective for asthma, the team’s findings also indicate that the presence of house dust components that stimulate the innate immune system decreases asthma risk.
Unlike conventional T cells, which belong to the adaptive arm of the immune response and take a few days before they are fully trained on a single, specific protein fragment or peptide antigen, MAIT and iNKT cells recognize molecular components common to many microbes. The team analyzed the frequency of different types of immune cells in blood collected from 110 one year-old study participants, the presence of immune-stimulatory components in the subjects’ house dust and asked whether any of the factors correlated with an increased of asthma at age seven.
Certain immune signatures such as having more MAITs that are protective in humans MAIT cells are unique in that they are borne to make gamma interferon, which could help skew the immune system toward an asthma-protective. And while the absolute numbers of iNKT cells had no bearing on asthma risk, the iNKT cell antigenic content in house dust from subjects’ houses did. iNKT activity reflects a home environment with increased microbe exposure and prevents asthma.
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