TNFRSF18 and head and neck squamous cell carcinoma: In five patients with SCCHN, PBMC were found to contain an average of 7±1.5% of CD4+CD25+ T cells, 5±1.0% of CD4+CD25+ GITR+ T cells and 6.0±1.3% of CD4+CD25+Foxp3+ T cells (Table 2).