Lars Lööf

Clinical and subclinical intestinal inflammation assessed by the mucosal patch technique: studies of mucosal neutrophil and eosinophil activation in inflammatory bowel diseases and irritable bowel syndrome

Background and aims: There is a clear need for a rapid, simple, safe, and sensitive method of determining the type and intensity of inflammation in the gut mucosa in clinical practice. In this study, we have evaluated the potential of a new method, the mucosal patch technique, in patients with and without apparent gut inflammation, as assessed by conventional diagnostic procedures. Subjects and methods: The technique tested is based on the idea that inflammatory mediators released from the rectal mucosa can be absorbed by and then extracted from cellulose patches brought into contact with the mucosa by use of an instrument with an inflatable balloon. Measurements were performed in healthy controls (n = 16) and in patients with active (n = 19) and inactive ulcerative colitis (UC, n = 8), collagen colitis (CC, n = 12), coeliac disease (n = 13), and irritable bowel syndrome (IBS, n = 13). Results: Inflammatory mediators from neutrophils (myeloperoxidase (MPO)) and eosinophils (eosinophil cationic protein (ECP)) were increased on average 300- and 10-fold, respectively, in patients with active UC compared with healthy controls and were correlated with the endoscopic score. Patients with inactive UC, CC, coeliac disease, and IBS exhibited no endoscopic signs of inflammation. These patient groups had significantly lower levels of MPO and ECP than the active UC group but showed on average a four- to sevenfold increase in MPO compared with healthy controls. Conclusion: The mucosal patch technique was well tolerated by patients and easily applied by the investigator. Pronounced neutrophil and eosinophil involvement in UC was demonstrated. With the high sensitivity of the technique, low degree mucosal neutrophil activation could also be quantified in patients with CC and UC in clinical remission. The finding of increased neutrophil involvement in patients with IBS contributes to the pathophysiological ideas of this disease.

IL-5 and TNF-alpha participate in recruitment of eosinophils to intestinal mucosa in ulcerative colitis.

There is an increased influx of activated eosinophils to the intestinal mucosa in active ulcerative colitis, and an increased release of eosinophil-derived proteins, such as ECP, has also been observed. These findings indicate that eosinophils may contribute to tissue damage and intestinal inflammation in this disease. The relative importance of different chemotactic factors and the impact of steroid treatment on their effect in active ulcerative colitis are not known. We measured the eosinophil chemotactic activity in perfusion fluids from 11 patients with ulcerative colitis before and after steroid treatment and from 7 control patients. The effect of neutralizing antibodies to IL-5 and -8, RANTES, eotaxin, MCP-3, TNF-α, GM-CSF was investigated. The chemotactic activity was higher in perfusion fluids from patients than from controls (P = 0.0043). Anti-IL-5 (P = 0.005) and -TNF-α (P = 0.017) inhibited the activity in perfusion fluids obtained before treatment. Steroid treatment prevented the effect of all antibodies but had no significant effect on the chemotactic activity. The chemotactic activity correlated with the levels of eosinophil granule proteins in the perfusion fluids. In conclusion, in ulcerative colitis, eosinophils are attracted to the intestinal tissue by chemotactic factors, of which IL-5 and TNF-α may be the most prominent steroid-sensitive ones. The steroid-insensitive chemotactic activities remain unidentified.

Challenge with gliadin induces eosinophil and mast cell activation in the jejunum of patients with celiac disease

PURPOSE The aim of this study was to clarify the role of eosinophils and mast cells in the small bowel in celiac disease. PATIENTS AND METHODS Patients with celiac disease (n = 10) were investigated by perfusion of a closed jejunal segment. The concentrations of certain granule constituents from eosinophils, eosinophil cationic protein (ECP), and from mast cells/basophils, histamine, were measured and the jejunal secretion rates of these cellular markers were calculated. RESULTS Compared with findings in healthy control subjects (n = 14), increased secretion rates were observed under basal conditions in patients with histopathologically active celiac disease. Gliadin, administered by perfusion to the jejunal segment, induced a fourfold increase in ECP secretion and a twofold increase of histamine secretion in patients with celiac disease (n = 7), but did not influence the secretion rates of these substances in healthy controls (n = 3). The secretion rate of ECP started to increase 20 minutes after challenge of the perfused segment with gliadin and reached maximum levels 40 minutes later. The secretion rate of histamine started to increase 40 minutes after gliadin administration. Concurrently with these inflammatory events, the secretion of albumin was doubled as a sign of increased mucosal leakage. CONCLUSION These data indicate that eosinophils and mast cells are both involved in the early gliadin-induced reactions of the small intestine, and suggest that these cells are effector cells participating in the celiac lesion of the mucosa.

Primary Biliary Cirrhosis—Phenotypic Characterization of Immunocompetent Cells in Peripheral Blood and Liver Tissue

Circulating T-cell subsets have been characterized in 18 patients with primary biliary cirrhosis (PBC) using a simple immunoenzymatic staining method on stored and prefixed cell samples. Furthermore, a double immunoenzymatic method was used to study T-cell subsets and their relationship to HLA-DR+ cells in frozen sections of liver biopsies from 12 patients with PBC. In 10 cases blood and liver samples were taken simultaneously from the same patient. Patients with PBC of early histological stage showed an elevated absolute number of helper/inducer T-cells (Leu 3a+) and reduced relative percentages of suppressor/cytotoxic T-cells (Leu 2a+) compared with healthy subjects resulting in an elevated helper/suppressor ratio. Liver biopsies in PBC were dominated by helper inducer phenotype T-cells in all cases irrespective of histological stage, penicillamine treatment or the relative levels of circulating T-cell subsets. A relatively high amount of HLA-DR+ cells were seen, several of these in close approximation to T-cells.