A joint study by Stanford University and the University of California, Berkeley and reported in the October issue of the Journal of Allergy and Clinical Immunology compared 71 participants in Fresno with 80 children, half with asthma and half without, from the relatively low-pollution city of Palo Alto, California. The children were matched by age, gender and asthma status, among other variables. The children were tested for breathing function, allergic sensitivity and T (Treg) cells in the blood. The study found that the children in Fresno had lower overall levels of Treg function and more severe symptoms of asthma than the children in Palo Alto. For example, the non-asthmatic children in Fresno had Treg function results that were similar to the children with asthma in Palo Alto leading researchers to conclude that exposure to dirty air is linked to decreased function of a gene that appears to increase the severity of asthma in children. For access to the complete study, please click here.