Some results showing no significant differences in airway eosinophilia used 129/Sv × C57BL/6 CD1d−/− mice (47), while those describing CD1d−/− and Jα18−/− mice as more resistant to asthma used CD1d−/− and Jα18−/− backcrossed with BALB/c animals (51). Here, CD1D is linked to asthma.