To further investigate whether the cytokine milieu in sepsis might affect T-cell homeostasis and thus be involved in the pathogenesis of septic lymphopenia, we measured the serum concentration of Interleukin-7 (IL-7), a key mediator of T-cell homeostasis and proliferation which was decreased in septic patients, improved survival in animal models of sepsis and increased lymphocyte numbers in septic patients [20]. Here, IL7 is linked to lymphopenia.