Faecal endotoxin and activity of the gut-associated lymphoid tissue in patients with malignant (B-cell) lymphoma

On the basis of previously obtained evidence that Gram-negative bacteria may influence the activity of leukaemia, a study of the composition of the flora, the immune stimulation by the Gram-negative bacteria and the endotoxin concentration in faeces was conducted in patients with low-grade malignant B-cell lymphoma as well as in patients with acute leukaemia. In these patients it was investigated whether the number of facultative anaerobic Gram-negative bacteria in the faeces correlated with endotoxin concentration. In addition, IgA coating of Gram-negative bacteria in the faeces was determined and the titre of circulating antibodies to endogenous Enterobacteriaceae species from the faeces of the corresponding patient was studied. No clear difference was found to exist in the percentage of IgA-coated Gram-negative bacteria in the faeces and in the circulating antibody titres to endogenous Enterobacteriaceae between healthy control persons, lymphoma patients and patients with acute leukaemia. Antimicrobial treatment to establish selective decontamination (SD) of Enterobacteriaceae species from the digestive tract did cause a significant decrease in the faecal endotoxin concentration in a subset of patients treated for SD with polymyxin.