However, previous studies have demonstrated an increased white cell TNF-α production in heterozygotes for the G-308A polymorphism.10 Moreover, in heart failure attributed mainly to ischaemic causes, plasma TNF-α concentrations are elevated to a similar degree in TNF-2 homozygotes compared to TNF-12 heterozygotes and TNF-1 homozygotes.12 Here, TNFSF12 is linked to heart failure.