CCR4 and allergic asthma: Of note, although dual-positive Th2/Th17 cells, expressing both CRTH2 and CCR6, have been found in higher frequencies in the peripheral blood and BAL from asthmatic patients and have been associated with exacerbation of chronic allergic asthma (14, 47), to our knowledge this is the first report of expansion of CCR4+CCR6+CRTH2+ Tem17.2 cells in the peripheral blood of helminth-infected patients.