Interestingly, this group found that the percentage of BTLA+CD4+ cells in patients who succumbed to sepsis were not significantly different from those who died from causes other than sepsis (both were at ~60 to 70% BTLA+); however, patients who died from lung cancer had lung CD4+ T cells that were increased to >80% BTLA+[13]. Here, CD4 is linked to lung carcinoma.