Increased levels of systemic LPS-positive bacterial extracellular vesicles in patients with intestinal barrier dysfunction

Correspondence to Prof An Hendrix, Laboratory of Experimental Cancer Research, Department of Radiation Oncology and Experimental Cancer Research, Ghent University, Ghent 9000, Belgium; an.hendrix@ugent.be We read with interest recent papers reporting on the impact of gut microbiota on several aspects of health and disease due to altered intestinal permeability resulting in systemic immune activation by pathogen-associated molecular patterns (PAMP), a process termed microbial translocation.1–4 Common to these studies is the analysis of systemic lipopolysaccharide (LPS), the major outer membrane PAMP of Gram-negative bacteria, to quantitatively assess microbial translocation. Online supplementary table 1 summarises individual patient characteristics; 25 donors asymptomatic of intestinal barrier dysfunction (12 healthy volunteers and 13 patients with cancer during chemotherapy without GI side effects suggestive for intestinal mucositis) and 24 patients with clinically well-defined intestinal barrier dysfunction (13 patients with IBD, 5 patients with cancer with radiation or chemotherapy-induced intestinal mucositis and 6 treatment-naive patients with HIV). [...]LPS-positive bacterial EV are present in plasma, are able to induce immune activation and correlate with impaired barrier integrity in patients diagnosed with IBD, HIV and cancer therapy-induced intestinal mucositis (figure 2).