CD28 and congenital bilateral aplasia of vas deferens from CFTR mutation: In a study involving patients with severe CAVD, Wu et al. observed the presence of CD8 +/CD28− T cells near the mineralized nodules of the aortic valve and a higher prevalence of circulating CD3+ T cells, namely the subset of CD8+ and CD57+ T cells expressing HLA-DR, in subjects with CAVD (Wu et al., 2007).