HLA-G and asthma: Taken together, the studies reported in this review suggest that: i) sHLA-G plasma levels are greater in atopic than in normal subjects and decrease after specific immunotherapy; ii) HLA-G is an asthma susceptibility gene; iii) HLA-G molecules are present in airway epithelium and BAL fluid of asthmatic subjects; iv) HLA-G is expressed and secreted by immune cells of atopic patients following in vitro allergenic challenge.