CCL11 and asthma: First, we applied an epidemiological study to test the primary hypothesized relationship between betel chewing and asthma as well as to investigate whether eotaxin-1 levels explain the association of betel chewing with asthma, which was supplemented by an in vitro experiment to demonstrate the functional link between arecoline pretreatment and a significant elevation of eotaxin-1 using cultured cell lines of both human normal dermal and gingival fibroblasts.