Also, it has been shown that various species of Streptococcus and Veillonella populate the small intestine47 and appeared to block IL-12p70 production, while augmenting IL-8, IL-6, IL-10, and TNF-a responses by dendritic cells in in-vitro assays48, indeed these cytokines have been linked to airway obstruction and severe asthma phenotype49–53. This evidence concerns the gene TNF and asthma.