Prophylactic ciprofloxacin treatment prevented high mortality, and modified systemic and intestinal immune function in tumour-bearing rats receiving dose-intensive CPT-11 chemotherapy

Infectious complications are a major cause of morbidity and mortality from dose-intensive cancer chemotherapy. In spite of the importance of intestinal bacteria translocation in these infections, information about the effect of high-dose chemotherapy on gut mucosal immunity is minimal. We studied prophylactic ciprofloxacin (Cipro) treatment on irinotecan (CPT-11) toxicity and host immunity in rats bearing Ward colon tumour. Cipro abolished chemotherapy-related mortality, which was 45% in animals that were not treated with Cipro. Although Cipro reduced body weight loss and muscle wasting, it was unable to prevent severe late-onset diarrhoea. Seven days after CPT-11, splenocytes were unable to proliferate (stimulation index=0.10±0.02) and produce proliferative and inflammatory cytokines (i.e., Interleukin (IL)-2, interferon-γ (IFN-γ), tumour necrosis factor-α (TNF-α) IL-1β, IL-6) on mitogen stimulation in vitro (P<0.05 vs controls), whereas mesenteric lymph node (MLN) cells showed a hyper-proliferative response and a hyper-production of pro-inflammatory cytokines on mitogen stimulation. This suggests compartmentalised effects by CPT-11 chemotherapy on systemic and intestinal immunity. Cipro normalised the hyper-responsiveness of MLN cells, and in the spleen, it partially restored the proliferative response and normalised depressed production of IL-1β and IL-6. Taken together, Cipro prevented infectious challenges associated with immune hypo-responsiveness in systemic immune compartments, and it may also alleviate excessive pro-inflammatory responses mediating local gut injury

Failure of Endotoxin to Protect C3H/HeJ Mice Against Lethal X-Irradiation

C3H/HeJ mice are more sensitive to lethal X-irradiation and cannot be protected by pretreatment with endotoxin, compared to the C3HeB/FeJ strain. Lack of a granulopoietic response in C3H/HeJ mice is evident

Tumor necrosis factor induced stimulation of granulopoiesis and radioprotection

Human recombinant tumor necrosis factor, TNF, was used to assess its ability to stimulate granulopoiesis and to protect mice against lethal irradiation, effects known to be inducable with TNF-rich postendotoxin serum from BCG infected mice (BCG/ET serum). Although the endotoxin contamination of this TNF preparation is extremely low its effects were compared in endotoxin low responder C3H/HeJ mice and susceptible NMRI mice. TNF is a potent inducer of serum colony stimulating activity, CSA, in both mouse strains. In peripheral blood a marked granulocytosis with a concomitant decrease in lymphocytes and monocytopenia occurs at 2 hours after injection of TNF. Moreover, TNF induces an increase in the number of splenic myelopoietic committed stem cells (GM-CFC, granulocyte-macrophage colony forming cells) determined five days after injection. The lethality rate, registered over 30 days after exposure to 660 cGy whole body X-irradiation is reduced to 40% in C3H/HeJ mice as compared to 75% in control animals. The reduction in lethality is observed both, when TNF was injected 24 hours before or after irradiation. In vitro, TNF significantly increases the number of colonies in the presence of CSA in bone marrow cultures. TNF per se does not effect colony growth. The studies reported here demonstrate that TNF is a myelopoiesis stimulating factor in mice which may be related to the reduction in lethality following whole body irradiation