GPR68 and Increased total eosinophil count: Apart from OGR1, TDAG8, another type of OGR1 family GPCR that couples with the cAMP pathway, is activated by an acidic pH of 7.0 to 6.0, resulting in the inhibition of eosinophil apoptosis and the exacerbation of airway inflammation of eosinophilia [36], inhibition of inflammatory cytokine production in macrophages [20], and inhibition of superoxide anion production in neutrophils [21].