Involvement of cytokines in cachexia induced by T-cell leukaemia in the rat.

The objective of this study was to investigate the involvement of cytokines (IL-1, IL-6 and TNF-alpha) in cachexia induced by T-cell leukaemia in the rat. Leukaemic rats exhibited a marked and significant increase in circulating IL-6 concentration from days 12-17 corresponding to the period of weight loss after induction of leukaemia. IL-6 plasma bioactivity correlated significantly with spleen weight and weight loss, implicating IL-6 in the cachectic response. In contrast, IL-1 and TNF-alpha plasma bioactivities were not increased compared to control rats, indicating that these cytokines are not circulating mediators of cachexia induced by T-cell leukaemia in the rat. These data suggest that IL-6 produced by the host may contribute to cachexia induced by T-cell leukaemia.