Previous studies have shown that activated T and B cells in gingival tissues of individuals with periodontitis express RANKL (receptor activator of nuclear factor κB ligand, also known as TNFSF11) (Taubman et al., 2005; Han et al., 2006, 2009; Kawai et al., 2006). The gene discussed is TNFSF11; the disease is periodontitis.