CD28 and Sepsis: The CD4+ T cell count, CD4+CD28+ T cell count, CD8+ T cell count and CD8+CD28+ T cell count were also significantly lower in elderly sepsis patients (194 versus 474, P<0.001; 180 versus 451, P=0.001;107 versus 199, P<0.001; 35 versus 132, P<0.001 respectively).