In addition, TNF-α-308-1 and TNF-α-308-2 alleles, IL-13 promoter polymorphisms, metalloproteinase (TIMP)-2 polymorphisms, and β2-adrenoceptor Gly16 polymorphism were proved to be significantly associated with the presence of smoking-related COPD [7]. This evidence concerns the gene TNF and chronic obstructive pulmonary disease.