To rule out effects of underlying immunological diseases or immunosuppressive medications, the immune functions of HPN
patients without active underlying immune-mediated diseases or immunosuppressive medications were compared with the immune function of healthycontrols. We focused on neutrophils, since these phagocytes seem to be particularly affected in patients on PN, as was exemplified by the increased risk for pneumonia and wound infections in mildly malnourished surgical patients. 5 To test the hypothesis that the first line of defense of the human immune system is not affected in patients on olive oil-based HPN, relevant aspects of the function of the innate immune system were deter-mined. Therefore, the capacity of leukocytes to eliminate Strepto-coccus pneumoniae, the expression of activation and degranulation
markers, and the stimulus-induced oxygen radical production of
leucocytes and (anti-)oxidant balances were determined under the
long-term influence of an OO-based parenteral nutrition
formulation.