Faecal tumour necrosis factor-alpha in individuals with HIV-related diarrhoea.

Objective: HIV-related gastrointestinal infection is associated with diarrhoea, weight loss, mucosal inflammation and increased intestinal permeability. As tumour necrosis factor (TNF)-alpha may mediate these features this cytokine was measured in the faeces of HIV-seropositive individuals with diarrhoea to assess its role in the pathogenesis of HIV-related gastrointestinal disease and the association with specific intestinal pathogens.
Design: Prospective study.
Methods: Two hundred and four HIV-seropositive individuals provided stool samples that were analysed for faecal TNF-alpha (FTNF-alpha) using a standard sandwich enzyme-linked immunosorbent assay.
Results: Stool from patients with bacterial, cytomegalovirus (CMV) and microsporidial diarrhoea had significantly elevated FTNF-alpha compared with those who had pathogen-negative diarrhoea (P < 0.05). FTNF-alpha was not raised in cryptosporidiosis, pathogen-negative or solid stool. In subjects with diarrhoea of more than 2 weeks duration and three stool samples negative for enteric pathogens, FTNF-alpha greater than 15 U/ml has a sensitivity of 88% and a specificity of 66% for the diagnosis of diarrhoea-related CMV enteritis.
Conclusion: TNF-alpha production may have a role in the pathogenesis of bacterial, microsporidial and CMV-related diarrhoea in HIV-seropositive individuals. Thus, anti-TNF-alpha agents may have a therapeutic role in the management of these conditions. FTNF-alpha greater than 15 U/ml in apparently pathogen-negative diarrhoea may suggest endoscopic gastrointestinal biopsy to diagnose CMV enteritis.