CCL2 and asthma: In contrast, the OVA-challenged PLCεΔX/ΔX mice exhibited reduced expression of Ccl2 and Cxcl2. We failed to detect the effect of the PLCε genotype on the expression of some cytokines implicated in the pathogenesis of asthma including IL-33[33], tslp[34], and Cx3cl1[35].