Disordered regulation of the in vitro immunoglobulin synthesis by intestinal mononuclear cells in Crohn's disease

Expression of the high-affinity IgG receptor FcRI (CD64) in patients with inflammatory bowel disease: a new biomarker for gastroenterologic diagnostics

OBJECTIVES

We sought to determine the quantitative expression of the high-affinity Fc receptor (CD64) on polymorphonuclear neutrophils (PMNs) in inflammatory and functional conditions of the intestine and investigated its correlation with clinical and biological parameters of inflammation.

METHODS

The quantitative expression of CD64 was determined by fluorescence-activated cell sorting analysis in patients with active or inactive inflammatory bowel disease (IBD, n=76), infectious enterocolitis, lactose and/or fructose intolerance, and healthy subjects.

RESULTS

The quantitative expression of CD64 in patients with active IBD (3,398+/-3,589 molecules per PMN, n=27) was significantly higher than in healthy subjects (607+/-265, n=28, P<0.001) or in patients with lactose/fructose intolerance (531+/-150, n=32, P<0.001). The expression of CD64 correlated significantly with C-reactive protein (CRP, 0.65, P<0.0001), Crohn's disease activity index (CDAI, 0.53, P<0.0001), and colitis activity index (CAI, 0.63, P<0.0001) in patients with IBD. With a cutoff point of 800, CD64 had a sensitivity of 88% and a specificity of 93% in discriminating between lactose/fructose intolerance and active IBD. The quantitative expression of CD64 in patients with infectious enterocolitis (19,190+/-8,920, n=22) was significantly higher than in patients with active IBD (P<0.001). With a cutoff point of 10,000, CD64 showed a sensitivity of 96% and a specificity of 97% in discriminating between infectious enterocolitis and active IBD.

CONCLUSIONS

CD64 could serve as a valuable tool to discriminate between IBD, infectious enterocolitis, and functional intestinal disorders.

Classifying esophageal motility by pressure topography characteristics: a study of 400 patients and 75 controls

AIM

This study aimed to devise a scheme for the systematic analysis of esophageal high-resolution manometry (HRM) studies displayed using topographic plotting.

METHODS

A total of 400 patients and 75 control subjects were studied with a 36-channel HRM assembly. Studies were analyzed in a stepwise fashion for: (a) the adequacy of deglutitive esophagogastric junction (EGJ) relaxation, (b) the presence and propagation characteristics of distal esophageal persitalsis, and (c) an integral of the magnitude and span of the distal esophageal contraction.

RESULTS

Two strengths of pressure topography plots compared to conventional manometric recordings were: (a) the ability to delineate the spatial limits, vigor, and integrity of individual contractile segments along the esophagus, and (b) the ability to distinguish between loci of compartmentalized intraesophageal pressurization and rapidly propagated contractions. Making these distinctions objectified the identification of distal esophageal spasm (DES), vigorous achalasia, functional obstruction, and nutcracker esophagus subtypes. Applying these distinctions made the diagnosis of spastic disorders quite rare: (a) DES in 1.5% patients, (b) vigorous achalasia in 1.5%, and (c) a newly defined entity, spastic nutcracker, in 1.5%.

CONCLUSIONS

We developed a systematic approach to analyzing esophageal motility using HRM and pressure topography plots. The resultant scheme is consistent with conventional classifications with the caveats that: (a) hypercontractile conditions are more specifically defined, (b) distinctions are made between rapidly propagated contractions and compartmentalized esophageal pressurization, and (c) there is no "nonspecific esophageal motor disorder" classification. We expect that pressure topography analysis, with its well-defined functional implications, will prove valuable in the clinical management of esophageal motility disorders.

Gut lavage fluid protein concentrations: objective measures of disease activity in inflammatory bowel disease

BACKGROUND

Fluid obtained by whole gut lavage normally contains traces of immunoglobulin (Ig) G, albumin, and alpha-1-antitrypsin; higher concentrations have been found in patients with inflammatory bowel disease (IBD).

METHODS

In a prospective study, 53 lavages were performed in 45 IBD patients (27 Crohn's disease, 18 ulcerative colitis), in whom disease activity was simultaneously assessed by Crohn's Disease Activity Index or Powell Tuck index. Concentration of IgG in lavage fluid was measured by enzyme-linked immunosorbent assay, and of albumin and alpha-1-antitrypsin by immunoturbidimetry.

RESULTS

For IgG, concentrations in lavage fluid correlated closely with activity indices: in Crohn's disease, r = 0.723 (P < 0.0001), in ulcerative colitis, r = 0.714 (P < 0.0001). Results for albumin and alpha-1-antitrypsin concentrations were similar to those for IgG, but they were less sensitive in detecting active disease. However, this method cannot be used as a diagnostic test for IBD; normal results were obtained for IgG in 6 (all inactive) of 42 lavages in patients who had unequivocal radiological or endoscopic abnormalities.

CONCLUSIONS

Assay of protein concentrations in gut lavage fluid is a simple, objective means of grading disease activity in patients with IBD; its potential uses are likely to be in the evaluation of complex cases and in clinical trials.

Immunoglobulin G (IgG), IgG1, and IgG2 determinations from endoscopic biopsy specimens in control, Crohn's disease, and ulcerative colitis subjects

Acute exacerbations of chronic inflammatory bowel disease (ulcerative colitis and Crohn's disease) are characterised by an increase in immunoglobulin G (IgG) positive cells in the mucosa, whereas uninflamed mucosa of inflammatory bowel disease patients displays only moderately increased or normal numbers of these cells. Previous data suggest that acute exacerbations of ulcerative colitis and Crohn's disease can be distinguished by different IgG subclass expression of mucosal immunocytes and a different IgG subclass production pattern of lamina propria lymphocytes. A procedure to obtain enough intestinal mononuclear cells from biopsy specimens to measure in vitro IgG and IgG1 production in control subjects and various patient groups has been established. IgG2 could be measured in Crohn's disease and ulcerative colitis only, as the concentrations in control subjects were below the sensitivity of the ELISA method. We found that IgG and IgG1 production correlated with the degree of local inflammation in both diseases, even in slightly inflamed mucosa, compared with control subjects. The proportion of IgG1 subclass was significantly increased in severely inflamed mucosa of both ulcerative colitis and Crohn's disease patients. A major difference between Crohn's disease and ulcerative colitis mucosa is apparent in mild or no inflammation. In Crohn's disease mucosa in remission, the IgG1/IgG ratio is comparable with that in controls, yet ulcerative colitis mucosa still displays significantly increased proportions of IgG1. In addition, the IgG2/IgG ratio is 0.12 in ulcerative colitis and 0.19 in Crohn's disease patients. The results show the dependence of local IgG and IgG1 production on the degree of inflammation and that an increase in subclass IgG1 in ulcerative colitis is present at all stages, including remission. These findings support the hypothesis that different immunoregulatory mechanisms are involved in Crohn's disease and ulcerative colitis. Environmental stimuli or genetic background may be responsible for the observed differences.

Gut lavage fluid proteins as markers of activity of inflammatory bowel disease

Intestinal secretions may be obtained by gut lavage using a polyethyleneglycol-based electrolyte lavage solution; concentrations of immunoglobulins and other proteins are readily measured in processed gut lavage fluid. As patients with inflammatory bowel disease (IBD) have greatly increased numbers of IgG-producing intestinal immunocytes, we measured gut lavage fluid IgG levels in 44 patients with IBD with various degrees of disease activity to determine whether total IgG in gut lavage fluid reflects disease activity. We also measured levels of albumin in gut lavage fluid, to determine the degree of plasma leakage. Both IgG and albumin levels in the patients with active IBD were significantly higher than those in controls and patients with inactive IBD (all p less than 0.00001). IgG is a more specific index of disease activity than albumin, with no overlap between levels in controls and patients with active IBD. There was a positive correlation (r = 0.68, p less than 0.0001) between IgG and albumin levels, suggesting that gut lavage fluid IgG is mainly plasma-derived.

Immunological study of histologically non-involved jejunum during Crohn's disease: evidence for reduced in vivo secretion of secretory IgA

We studied the local humoral immunity of histologically non-involved jejunum in patients with Crohn's disease. Normal subjects and patients with ulcerative colitis served as controls. Jejunal fluid samples were collected during segmental jejunal perfusion, under an occluding balloon and the in vivo jejunal secretion of the following proteins was determined: albumin, orosomucoid, transferrin, alpha 2-macroglobulin, secretory component, monomeric and polymeric IgA, IgG, and IgM. The densities and number of IgA-, IgG-, and IgM-containing cells in the lamina propria of the jejunum were measured on perendoscopic biopsies. Jejunal secretion of polymeric IgA and the density of IgA-containing plasma cells in the lamina propria were significantly lower in patients with Crohn's disease than in both control groups. This abnormal intestinal immune response, which was not correlated to the activity of the disease, might be involved in its pathogenesis.

Effect of human intestinal macrophages on immunoglobulin production by human intestinal mononuclear cells isolated from patients with inflammatory bowel disease

The effect of macrophages on spontaneous immunoglobulin production by isolated human intestinal mononuclear cells (MNC) is unknown. Depletion of macrophages by adherence to fibronectin or by panning with macrophage-specific monoclonal antibody 3C10 lead to a significant reduction in IgA. IgG and IgM production by intestinal MNC from both normal (n = 10) and inflammatory bowel disease (IBD) (n = 13) mucosa. The reduction in immunoglobulin produced by macrophage-depleted intestinal MNC was greater in IBD patients than in normal controls. There was a significant correlation (r = 0.816, P less than 0.001) between the percentage of macrophages depleted by panning with 3C10 and the reduction in IgG produced by macrophage-depleted intestinal MNC. Addition of either fibronectin-adherent cells or the supernatant from these macrophage-enriched cells enhanced immunoglobulin production in a dose-dependent fashion. A greater increase in IgG production by macrophage-depleted cells was seen when cultured with supernatant from inflamed IBD mucosal cells, compared with that from normal mucosal cells. The soluble factor(s) responsible in the supernatant was acid and heat susceptible but was not affected by freezing and thawing. Addition of recombinant human interleukin-1 beta or human interferon-gamma to cell cultures did not influence immunoglobulin production. Thus, human intestinal macrophages enhance spontaneous immunoglobulin production by isolated intestinal MNC by secreting soluble factor(s) which remain to be fully characterized.

Impaired local natural killer cell activity in human colorectal carcinomas

The present study was undertaken to study natural killer (NK) cell activity in patients with colorectal cancer at peripheral and local levels. Mononuclear cells were isolated from uninvolved colorectal mucosa, tumor tissue and peripheral blood, and tested against the colon carcinoma cell line CaCo-2 and the erythroleukemia cell line K-562. Peripheral blood NK cell activity from the patients showed similar levels compared with healthy controls, whereas, mononuclear cells of tumor tissue were found to have a significantly decreased NK cell activity compared to the normal intestinal mucosa (P less than 0.01). No relation was found between the NK cell activity and the advancement of the disease according to the Duke's stage. Interferon-gamma (IFN-gamma) stimulated the NK cell activity of the mononuclear cells from blood, mucosa and tumor. However, the increase of NK cell activity after IFN-gamma stimulation was lower in the tumor compared to the mucosa (P less than 0.02). The lectin, phytohaemagglutinin, increased the cytotoxicity of mononuclear cells from blood, mucosa and tumor to a similar level. These results suggest that patients with colorectal tumors exhibit a normal NK cell activity in peripheral blood and intestinal mucosa; however, a diminished NK cell activity exists at the tumor level. Although mononuclear cells isolated from the tumor have a normal response to lectin stimulation they show hyporesponsiveness to IFN-gamma stimulation with regard to their NK cell activity.