EBI3 and chronic obstructive pulmonary disease: EBI3 subunit has sequence homology with IL-12p40,8 and the heterodimeric IL-27p28 chain belongs to the family of long-chain 4-helix bundle cytokines and displays sequence homology to IL-12p35 and IL-23p19.9 Recently, the associations of IL-27 -964 A/G, 2905 T/G, and 4730 T/C polymorphisms with the risk for various diseases were investigated and the relationships between -964 A/G and the risk for several diseases such as asthma,10 chronic obstructive pulmonary disease (COPD),11 and inflammatory bowel disease (IBD12) have been identified.