CYTOKINE DETECTION AND MODULATION IN ACUTE GRAFT-VS-HOST DISEASE IN MICE

A MURINE model for acute lethal graft vs. host disease (GVHD) was used to study the role that a number of cytokines play in the development of lethal GVHD. In this study we focused on the role of IL-1, IL-2, IL -4, IL-6, IFN-gamma and TNF-alpha. Lethally irradiated (C57BL x CBA)F1 mice were reconstituted either with 10(7) allogeneic BALB/c spleen ce lls or with a similar number of syngeneic cells, as a control. A signi ficant rise in serum levels of IL-6, TNF-alpha and IFN-gamma levels wa s found in allogeneically reconstituted mice. This is in contrast to t he syngeneic control group in which no rise was seen. Serum IL-2 and I L-4 levels were below the detection limit. In the supernatant of Con A stimulated spleen cells from allogeneically reconstituted mice IL-6, IFN-gamma and TNF-alpha concentrations were increased. The expression of mRNA for cytokines as detected by reverse transcription PCR was stu died in spleen cells. In the allogeneic reconstituted mice the mRNA ex pression of IL-1alpha, IL-2, IL-6, IFN-gamma and TNF-alpha displayed f aster kinetics compared with that in syngeneic reconstituted mice. The effect of treatment with recombinant cytokines, antibodies to cytokin es and to cytokine receptors on the development of GVHD was investigat ed. Administration of recombinant IL-2 to allogeneically reconstituted mice strongly increased the morbidity and mortality whereas injection of IL-1alpha and TNF-alpha did not influence survival. Administration of antibodies against IL-2 or the IL-2 receptor decreased the morbidi ty and mortality. Anti-IL-6, anti-IFN-gamma and anti-TNF-alpha mAB, on the other hand, did not affect the morbidity and mortality of GVHD. T he results of this study suggest successive waves of cytokine-secretin g cell populations consistent with the induction of an inflammatory re sponse in the development of acute GVH disease.