Histochemical comparison of the epithelial mucins in the ileum in Crohn''s disease and in normal controls.

A comparison of routine and special histochemical methods that were applied to the epithelial mucins of small intestine from patients with Crohn's disease and from normal controls showed that the normal small intestine (ileum) goblet cells secrete a predominantly non-sulphated sialomucin and that, in contradistinction to the colon, the neuraminidase insensitivity of the sialic acids of the small intestine was not due to either O-acylation at C4 or an ester substituent at C1. Presumably this implies that the protection against enzyme attack afforded to the mucosa by the mucin coat in the small intestine utilises a different mechanism from that in the colon and that, although in many respects the small intestinal mucins in Crohn's disease, and in normal controls are similar, there is an increase in side-chain O-acylated sialic acids in such mucins in Crohn's disease. This difference has not been described before, probably because it can be seen only after staining such sections by the PAT/KOH/PAS and the PBT/KOH/PAS techniques.     

Antibodies to maize in patients with Crohn''s disease, ulcerative colitis and coeliac disease.

The incidence of antibodies to maize using an immunofluorescent technique has been found to be 14% in controls, 33% in Crohn's disease, 50% in ulcerative colitis and 44% in coeliac disease. This result indicates that humoral immunity to maize is probably unimportant in the pathogenesis of Crohn's disease. The similar incidence of antibodies in the inflammatory bowel disease and coeliac groups suggests absorption of dietary antigen secondary to an increased mucosal permeability.     

Anti-neutrophil nuclear antibody in ulcerative colitis, Crohn''s disease and primary sclerosing cholangitis.

We have previously described circulating autoantibodies to a portal tract antigen in patients with primary sclerosing cholangitis. In this study the antigen has been shown by double-labelling studies to be specifically located in the nuclei of tissue neutrophils. Using isolated peripheral blood neutrophils and an immunoperoxidase technique, anti-neutrophil nuclear antibody (ANNA) was found in the serum of 84% of patients with primary sclerosing cholangitis (PSC: n = 32) with a median titre of 1/1000 and a peak titre of 1/500,000. ANNA was also detected in 86% of patients with inflammatory bowel disease alone (IBD: n = 76) with a median titre of 1/10 and a peak titre of 1/10,000. In contrast, only 12% of controls had ANNA, and in none was the titre greater than 1/10. In PSC the ANNA titre correlated with the serum aspartate transaminase concentration, suggesting that it is related to disease activity. In IBD the titre of ANNA was significantly higher in patients with recently active disease. There was no significant difference between the titres seen in ulcerative colitis and Crohn's disease. ANNA was not associated with neutropaenia. The results provide further evidence of involvement of autoimmune mechanisms in inflammatory bowel disease and primary sclerosing cholangitis.     

Circulating antibodies to heat-shock protein 60 in Crohn''s disease and ulcerative colitis.

Heat-shock proteins (HSPs) are highly conserved immunogenic intracellular molecules that are induced by inflammatory mediators and may induce autoimmune phenomena in vivo. We have recently demonstrated the increased expression of HSP-60 in the colonocytes of patients with ulcerative colitis. To study further the role of HSP-60 in inflammatory bowel disease, we have now measured antibodies to recombinant mycobacterial HSP-65 (a member of the HSP-60 family) in patients with Crohn's disease, ulcerative colitis, healthy volunteers and, as disease controls, patients with confirmed bacterial diarrhoea. In comparison with healthy controls (n = 20; median level of 89 ELISA units; range 24-292), serum IgA HSP-60 antibodies were elevated in Crohn's disease (n = 21; 157; 57-364; P < 0.05) and active ulcerative colitis (n = 16; 188; 58-373; P < 0.01) but not bacterial diarrhoea (n = 10; 106; 51-285). Increased IgA HSP-60 antibody levels in patients with inflammatory bowel disease may occur as the result of HSP release from injured gut epithelium; alternatively, increased intestinal permeability could facilitate mucosal access of luminal antigens and the generation of cross-reactive anti-bacterial HSP antibodies.     

Basis of sialic acid heterogeneity in ulcerative colitis.

To test the suggestion that an inherited defect in colonic mucus rendering it susceptible to degradation by bacterial enzymes may be an important factor in the aetiology of ulcerative colitis, 650 colonoscopic and rectal biopsy specimens from 166 patients with colitis were stained by mild periodic acid Schiff (mPAS), which shows sialic acid that is deficient in O-acetyl substituents. There was an excess of mPAS positive sialic acid in patients with chronic ulcerative colitis, but the increased expression was patchy and coincided with a morphological change in the form of epithelial hyperplasia (metaplasia). Hyperplasia was more common in the rectum and in women and was associated with, and presumably secondary to, active inflammation. It is concluded that variation in the structure of sialic acid is acquired and is therefore unlikely to be implicated in the aetiology of ulcerative colitis.     

A morphological assessment of immunoreactivity in colonic Crohn''s disease and ulcerative colitis by a study of the lymph nodes

The mesenteric lymph nodes in total colectomy specimens from patients with ulcerative colitis or Crohn's colitis were assessed for immunological reactivity. Despite the suggestion of previous work using different methods that immunological difference between the diseases exist and may be important in pathogenesis, no significant differences were found in this study. Changes were observed in both diseases and when ulceration was present these consisted of both cellular and humoral immune reactivity. There was no evidence of diminished cell-mediated immunity in Crohn's disease and the presence of granulomata did not constitute any special immunological group.     

Immunoglobulin production by isolated intestinal mononuclear cells from patients with ulcerative colitis and Crohn''s disease.

We studied immunoglobulin production by isolated intestinal mononuclear cells from 25 patients with active inflammatory bowel disease (IBD) and 17 controls undergoing surgical resections for intestinal tumour or other disorders. Normal ileal intestinal mononuclear cells spontaneously produced greater amounts of IgA and IgM than did normal colon cells. In cells from patients with IBD there was a significantly reduced IgA production, but production of IgG was enhanced in both colon and ileum. The alteration in IgA and IgG production in IBD was confirmed by comparing the immunoglobulin production by mononuclear cells from inflamed with that from non-inflamed areas of mucosa in six patients with distal ulcerative colitis. The proportion of IgA-containing cells in isolated intestinal mononuclear cells from IBD mucosa was less than normal. However, the proportion of IgG-containing cells from IBD mucosa was not increased in isolated intestinal mononuclear cells although they produced more IgG than normal mucosal cells. Our study showed an altered pattern of immunoglobulin production by intestinal mononuclear cells isolated from patients with inflammatory bowel disease.     

Antineutrophil cytoplasmic antibodies (ANCA) directed against cathepsin G in ulcerative colitis, Crohn''s disease and primary sclerosing cholangitis.

Autoantibodies directed against polymorphonuclear neutrophils (PMN) have been observed in serum from patients with ulcerative colitis (UC), Crohn's disease (CD) and primary sclerosing cholangitis (PSC) using indirect immunofluorescence and fixed granulocyte ELISA. Our study demonstrates the presence in the serum of these patients of autoantibodies which bind to an azurophilic granule component distinct from proteinase 3, elastase and myeloperoxidase. These autoantibodies thus belong to the ANCA family, but their antigen specificity differs from the already characterized ANCA antigens. We have found that the same ANCA antigen target, named UC-antigen, was recognized by serum IgG from patients with UC, CD and PSC. It was purified by Matrex Gel Orange A dye affinity chromatography and subsequent immunoabsorption of contaminant proteinase 3 with immobilized anti-proteinase 3 MoAb. The identity between this UC antigen and cathepsin G was demonstrated by their coelution from Matrex Gel Orange A column and the parallel titration of cathepsin G-specific enzymatic activity and UC-ANCA binding, both in partially purified UC antigen and in highly pure cathepsin G. Furthermore, the use of cathepsin G ELISA confirmed that UC, CD and PSC patients' IgG did indeed bind to cathepsin G. Comparison of the results obtained with azurophilic granule- and cathepsin G-ELISA as well as inhibition of ANCA binding by anti-cathepsin G polyclonal antibodies, revealed that in some patients cathepsin G is the main azurophilic granule target of ANCA while others have other ANCA specificities. The fact that UC, CD and PSC are frequently associated with cathepsin G ANCA, while rarely occurring in other types of vasculitis, is intriguing but suggests that these diseases may have a common pathogenetic mechanism.     

Biochemical analysis of enzymic markers of inflammation in rectal biopsies from patients with ulcerative colitis and Crohn''s disease.

Rectal biopsies were collected from control subjects, patients with ulcerative colitis both active and quiescent, and from patients with Crohn's disease, both with and without rectal involvement, as judged by histological assessment. Tissue homogenates were assayed for neutrophil (vitamin B12 binding protein, myeloperoxidase, lysozyme) and lymphocyte (5' nucleotidase) selective markers. Patients with acute but not those with quiescent colitis had striking increases of the neutrophil markers. Neither patient group with ulcerative colitis showed a change in the lymphocyte marker enzyme activity. Patients with Crohn's disease involving the rectum showed significant, but less marked, increases in the activity of the neutrophil markers that were found in active ulcerative colitis. Patients with Crohn's disease, not involving the rectum, showed normal or reduced levels of neutrophil markers. Patients with Crohn's disease, both those with and without rectal involvement, had increased activities of the lymphocyte selective marker. This distinguishes this inflammatory response from that of ulcerative colitis and provides further biochemical evidence of abnormalities in apparently uninvolved mucosa from Crohn's patients.     

Immune complexes in ulcerative colitis and Crohn's disease.

Sera from 156 patients with ulcerative colitis and Crohn's disease were tested for the presence of immune complexes, by the detection of anti-complementary activity and 125I-labelled Clq precipitation. Using aggregated IgG, a comparison between the two tests indicated that the anti-complementary test was most sensitive to aggregates of 11S in size, while the 125I-labelled Clq test detected aggregates over 20S in size. Excess anti-complementary activity was common in patients with active bowel disease, and in those with extra-intestinal manifestations, particularly acute arthritis, ankylosing spondylitis and liver disease. Large complexes were only common in patients with liver disease. Immune complexes in the gut mucosa may play a role in the pathogenesis of these diseases, and the deposition of circulatory immune complexes may explain at least some of the extra-intestinal manifestations.     

ERK controls epithelial cell death receptor signalling and cellular FLICE-like inhibitory protein (c-FLIP) in ulcerative colitis

Intestinal epithelial cell (IEC) death signalling through the Fas receptor is impaired in active ulcerative colitis (UC). This is possibly due to the activation of cytoprotective pathways resulting in limitation of the tissue injury secondary to inflammation. We hypothesized that inflammatory signalling like the nuclear factor (NF)-κB or mitogen activated protein kinase (MAPK) pathways could be involved in (a) the modification of Fas mediated apoptosis responses and (b) the regulation of the Fas receptor inhibitor cellular FLICE-like inhibitory protein (c-FLIP). Phospho-ERK was upregulated in IECs in active UC as well as IECs exposed to pro-inflammatory cytokines in vitro. Similarly, the short form of c-FLIP (c-FLIP_S) was found to be upregulated in IECs from patients with active UC. c-FLIP_S was the main splice variant found in both HT-29 cells and primary human IECs. Both splice variants were induced by TNF-α, IL-1β and IFN-γ, while IL-10 induced c-FLIP_L expression; TNF-α also induced c-FLIP_S in primary IECs. Inhibition of NF-κB, JNK and p38 pathways did not affect c-FLIP expression, whereas ERK inhibition by MEK1 RNA silencing and pharmacologic inhibitors decreased c-FLIP_S expression. Similarly, ERK – but not NF-κB – inhibited Fas ligand and TNF-α-mediated apoptosis responses in both cell line experiments and primary IECs. The present study identifies the MEK-ERK pathway as a major regulator of apoptosis in IECs during flares of UC and an inducer of c-FLIP_S. The results explain the resistance to receptor mediated epithelial apoptosis in active UC. Oncogenic c-FLIP could promote propagation of DNA-damaged IECs and contribute to cancer development in UC.     

C3 metabolism in ulcerative colitis and Crohn's disease.

The metabolism of the third component of complement (C3) has been investigated in four patients with ulcerative colitis, three patients with Crohn's disease and seven control subjects, using radioiodinated C3 prepared from fresh human plasma. Both the fractional catabolic rate and synthesis rate of C3 were increased in the patients with inflammatory bowel disease, although the serum-C3 levels were normal or raised. The results suggest that complement activation may play a role in the pathogenesis of mucosal inflammation in these diseases.     

Spontaneous secretion of IgG subclasses by intestinal mononuclear cells: differences between ulcerative colitis, Crohn's disease, and controls

Spontaneous IgG and IgG subclass secretion patterns by isolated intestinal mononuclear cells (MNC) from control and inflammatory bowel disease (IBD) specimens were examined. Intestinal MNC from IBD specimens spontaneously secreted more total IgG than did control intestinal MNC. This increased spontaneous IgG secretion by ulcerative colitis intestinal MNC was primarily due to markedly increased production of IgG1. Slightly increased secretion of IgG3, but not IgG2 by ulcerative colitis intestinal MNC was present when compared with control and Crohn's disease intestinal MNC. In contrast, Crohn's disease intestinal MNC exhibited increased spontaneous secretion of all the IgG subclasses examined, with IgG2 being predominant.     

Crohn''s disease and the mycobacterioses: a review and comparison of two disease entities.

Crohn's disease is a chronic granulomatous ileocolitis, of unknown etiology, which generally affects the patient during the prime of life. Medical treatment is supportive at best, and patients afflicted with this disorder generally live with chronic pain, in and out of hospitals, throughout their lives. The disease bears the name of the investigator who convincingly distinguished this disease from intestinal tuberculosis in 1932. This distinction was not universally accepted, and the notion of a mycobacterial etiology has never been fully dismissed. Nevertheless, it was 46 years after the distinction of Crohn's disease and intestinal tuberculosis before research attempting to reassociate mycobacteria and Crohn's disease was published. Recently, there has been a surge of interest in the possible association of mycobacteria and Crohn's disease due largely to the isolation of genetically identical pathogenic Mycobacterium paratuberculosis from several patients with Crohn's disease in the United States, the Netherlands, Australia, and France. These pathogenic organisms have been isolated from only a few patients, and direct evidence for their involvement in the disease process is not clear; however, M. paratuberculosis is an obligate intracellular organism and strict pathogen, which strongly suggests some etiologic role. Immunologic evidence of a mycobacterial etiology, as assessed by humoral immune determinations, has been conflicting, but evaluation of the more relevant cellular immunity has not been performed. Data from histochemical searches for mycobacteria in Crohn's disease tissues have been equally conflicting, with acid-fast bacilli detected in 0 to 35% of patients. Animal model studies have demonstrated the pathogenic potential of isolates as well as elucidated the complexity of mycobacterial-intestinal interactions. Treatment of Crohn's disease patients with antimycobacterial agent has not been fully assessed, although case reports suggest efficacy. The similarities in the pathology, epidemiology, and chemotherapy of Crohn's disease and the mycobacterioses are discussed. The issue is fraught with controversy, and the data generated on the association of mycobacteria and Crohn's disease are in their infantile stages so that a general conclusion on the legitimacy of this association cannot be made. While no firm evidence clearly implicates mycobacteria as an etiologic agent of Crohn's disease, the notion is supported by suggestive and circumstantial evidence and a remarkable similarity of Crohn's disease to known mycobacterial diseases.     

Humoral reaction in the inflamed colon in Hirschsprung''s disease and ulcerative colitis.

An immunological study of B cells in patients with colitis that was associated with Hirschsprung's disease was undertaken and compared with that in patients with ulcerative colitis and in normal controls. There was an appreciable increase in IgA and a decrease in IgG in both disease groups. Humoral reaction in colitis associated with Hirschsprung's disease seems to be indistinguishable from that in ulcerative colitis and possibly in other inflammatory bowel diseases.