For example, Thorsen et al. examined the airway microbiota in a cohort of 700 children monitored for the development of asthma since birth: they concluded that microbial diversity in the airways at age one month were associated with asthma by age 6 years, and a higher relative abundance of Veillonella and Prevotella is furthermore associated with reduced TNF-α and IL-1β and increased CCL2 and CCL17, which itself is an independent predictor for asthma [60]. Here, CCL17 is linked to asthma.