Table 3.

Studies on relationship between tumour necrosis factor (TNF) gene polymorphisms and COPD

Polymorphisms	Study type	Subjects	Populations	Significance	Refs
TNF-308	Meta-analysis	2380 COPD cases and 3738 controls	Asian and Caucasian	TNF-308 A allele might be a risk factor for developing COPD among Asian populations, but not among Caucasians	21
TNF gene complex polymorphism (LtalphaNcoI*1/2)	Association study	66 COPD cases, 23 participants with disseminated bronchiectasis, 45 participants with non-obstructive pulmonary disease and 98 controls	Caucasian	TNF gene complex polymorphism did not seem to play a major role as genetic risk factor in COPD	22
TNF-308	Association study	84 COPD patients	Japanese	TNF-308 A allele might be partly associated with the extent of emphysematous changes in patients with COPD	63
TNF-308	Association study	106 COPD patients and 99 controls	Caucasian	There was no increased frequency of the A allele in patients compared to control participants. AA homozygous patients had less reversible airflow obstruction and a significantly greater mortality	60