Lactoferrin effects on the in vitro immune response in critically ill patients

The aim of the study was to investigate whether lactoferrin can improve the immune competence of cells from patients with systemic inflammatory response syndrome (SIRS). We studied the effect of lactoferrin (LF) on the proliferative response of peripheral blood mononuclear cells (PBMC) to lipopolisaccharide (LPS) in vitro and its influence on production of 2 proinflammatory cytokines: interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha). Three groups of patients: septic survivors, septic nonsurvivors and multiple trauma patients, were investigated. Blood samples were taken upon admission to intensive care unit and after 2, 3 and 5 days. The proliferative response of PBMC in vitro was tested using 3-day culture with LPS. Cell proliferation/death was measured using MTT colorimetric method. The spontaneous and LPS-induced activity of TNF-alpha and IL-6 were measured with bioassays using indicator cell lines WEHI-164.13 and 7TD1, respectively. We demonstrated that LF inhibited the proliferative response, both spontaneous and LPS-induced, in all groups of patients. Lactoferrin alone was a good inducer of IL-6 and TNF-alpha production by monoclear cells in vitro. Addition of LF to the cultures of LPS-activated mononuclear cells stimulated IL-6 production, most markedly in the group of septic survivor patients (mean 1479, 1452, 1728, 1980 pg/ml on day 1, 2, 3 and 6 respectively). Lactoferrin also upregulated TNF-alpha production. That effect was very significant in the septic survivor patients (mean 7407, 6739, 7498 and 8509 pg/ml on day 1, 2, 3 and 5 respectively) and less pronounced in the group of trauma patients. We conclude that lactoferrin exhibited regulatory actions on the altered reactivity of PBMC from patients with sepsis and multiple injury. Lactoferrin is a good inducer of IL-6 and TNF-alpha production. However, in most cases of septic nonsurvivors LF could not abolish low reactivity of cells with regard to cytokine production.