The relative levels of cytokine gene expression in the liver were analysed,
focusing on IL-2, IL-4, IL-5, IL-6 and IFN-gamma compared to those in the
spleen and Peyer's patch by using the reverse transcriptase polymerase chai
n reaction (RT-PCR). The levels of expression of cytokines in the liver mon
onuclear cells (MNC), especially that of IL-6, were significantly higher th
an in other organs when mice were reared under specific pathogen-free (SPF)
or conventional conditions. Both the spleen and Peyer's patch MNC expresse
d little of any of the cytokines, except for IL-4 in Peyer's patch MNC. The
liver MNC produced significant amounts of IL-6 in the culture supernatant
upon concanavalin A stimulation. These findings suggest that the liver is a
potent IL-6-producing organ, which may relate to B cell differentiation, l
iver regeneration and the induction of acute phase proteins.