LPS responsiveness of leukocytes and opsonic capacity of plasma from premature infants with and without the addition of interferon-γ.

<p>(A) Whole blood from 7 extremely premature infants (born before 28 wks of gestational age) was treated <i>ex vivo</i> or not for 12 hrs with interferon (IFN)-γ. LPS was then added for an additional 12 hrs and IL-6, TNF-α, and IL-10 were measured (mean ± SEM) in conditioned plasma. (B) The plasma from whole blood obtained in seven extremely premature infants (born before 28 wks of gestational age) treated <i>ex vivo</i> or not with for 12 hrs with IFN-γ was incubated with fluorescent <i>E.coli</i>, <i>S.aureus</i> and <i>S.epidermidis</i> (opsonisation). Opsonised bacteria were then incubated with neutrophil-like HL-60 cells for 40 min; intracellular fluorescence was measured by flow cytometry, and expressed as mean phagocytic index (± SEM). Statistical significance was tested with Wilcoxon matched-pairs signed rank test.