Spontaneous release of Interferon γ by intestinal lamina propria lymphocytes in Crohn's disease. Kinetics of in vitro response to interferon γ inducers

Abstract

The spontaneous induced release of interferon γ (IFN γ) by cultured intestinal lamina propria lymphocytes was investigated in patients with Crohn's disease. In contrast to normal lymphocytes, intestinal lymphocytes from these patients spontaneously released IFN γ and seemed to contain IFN γ in their cytoplasm. Autologous peripheral lymphocytes did not release IFN γ. When stimulated with interferon inducers lamina propria lymphocytes from Crohn's disease tissue showed an increase in IFN γ release 24 hours after induction with no appreciable further increase over the next two days of culture, while in control cells, either peripheral or intestinal, IFN γ release progressively increased, peaking 72 hours after induction. These findings indicate that in Crohn's disease the intestinal lymphocytes are stimulated in vivo to produce IFN γ and that the spontaneous IFN γ production is compartmentalised to the gut lymphocytes. These data support the concept that locally released IFN γ has a crucial role in cell interactions in the lamina propria and contribute to the locally occurring immune phenomena in Crohn's disease, including the increased epithelial expression of major histocompatibility complex class II antigens.