In a study by Twuet et al., researchers analyzed 18 hearts from AIDS patients (with and without cardiomyopathy) and found that those with cardiomyopathy had significantly higher levels of gp120 and tumor necrosis factor-alpha (TNF-α), both of which were associated with cardiomyocyte apoptosis. This evidence concerns the gene ITIH4 and cardiomyopathy.