In vitro anticolon antibody production by mucosal or peripheral blood lymphocytes from patients with ulcerative colitis

Plasmablast frequency and trafficking receptor expression are altered in pediatric ulcerative colitis

BACKGROUND

The incidence of pediatric ulcerative colitis (UC), a chronic autoinflammatory disease of the colon, is on the rise. Although an increased infiltration of B cells from the peripheral blood into the colon occurs in UC, B-cell trafficking is understudied. We hypothesized that the frequency of circulating plasmablasts (PBs) and their trafficking receptor (TR) expression may be indicative of the location and degree of pathology in pediatric UC.

METHODS

We conducted multicolor flow cytometry analyses of circulating IgA(+/-) PBs and IgA(+) memory B cells (MBCs) in pediatric UC patients with remission, mild, moderate, and severe state of disease (n = 12), and healthy pediatric (n = 2) and adult donors (n = 11).

RESULTS

Compared to healthy donors the average frequency of PBs among total peripheral blood lymphocytes is increased 30-fold during severe UC activity, and positively correlates with Pediatric Ulcerative Colitis Activity Index score, C-reactive protein level, and erythrocyte sedimentation rate. A greater percent of PBs in severe patients express the gut-homing receptors α4β7 and CCR10, and the inflammatory homing molecule P-selectin ligand (P-sel lig). The percent of IgA(+) MBCs expressing α4β7, however, is reduced. Furthermore, expression of the small intestine TR CCR9 is decreased on α4β7(high) PBs, and on α4β7(high) /CCR10(high) PBs and MBCs in these patients, consistent with preferential cell targeting to the colon.

CONCLUSIONS

Peripheral blood PBs with a colon-homing phenotype (α4β7/CCR10/P-sel lig) are elevated in children with severe UC. Screening this B-cell subset may provide a complementary approach in monitoring disease activity or therapeutic efficacy in pediatric UC.

The role of cytokines in inflammatory bowel disease

Cytokines play an important role in the development and persistence of the inflammatory lesions seen in Crohn's disease and ulcerative colitis. This review discusses the current thinking of the role of cytokines in chronic intestinal inflammation including the involvement of immunoregulatory cytokines within the Th1 and Th2 subsets.

Increased numbers of immature plasma cells in peripheral blood specifically overexpress chemokine receptor CXCR3 and CXCR4 in patients with ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease featuring infiltration by plasma cells producing immunoglobulins. We have reported previously the specific and significant proliferation of immature plasma cells in the inflamed colonic and pouch mucosa of UC patients. The aim of this study was to characterize peripheral blood immature plasma cells and the migration mechanisms of such immature plasma cells to inflamed sites in UC. The characteristics of peripheral blood immature plasma cells and chemokine receptor expression were examined by flow cytometry. Expression of mucosal chemokine was quantified using real-time reverse transcription-polymerase chain reaction and immunohistochemistry. The number of peripheral blood immature plasma cells was significantly higher in patients with active UC and active Crohn's disease (CD) than in healthy controls. The proportion of immature plasma cells was correlated positively with clinical activities of UC and CD. Many peripheral blood immature plasma cells were positive for CXCR3, CXCR4, CCR9 and CCR10. Expression of CXCR3 and CXCR4 in UC patients was significantly higher than in controls. CXCL9, CXCL10 and CXCL11 mRNA levels in colonic mucosa of inflamed IBD were higher than in controls. Immunofluorescence study also showed abundant CXCR3-positive immature plasma cells in the inflamed colonic mucosa of UC. Increased numbers of immature plasma cells may migrate towards inflammatory sites of UC via the CXCR3 axis, and may participate in UC pathogenesis.

Antibody to tropomyosin isoform 5 and complement induce the lysis of colonocytes in ulcerative colitis

OBJECTIVES

Tropomyosins (TMs) are cytoskeletal microfilament proteins present in all eukaryotic cells. Human TM isoform 5 (hTM5) is the predominant isoform in colonic epithelial cells. Antibodies against hTM5 are found both in the sera and in the mucosa of patients with ulcerative colitis (UC) but not Crohn's disease (CD). We investigated whether anti-hTM5 autoantibodies are pathogenic.

METHODS

Normal-appearing colonic mucosal biopsy specimens were incubated with autologous serum. After 45 min, deposition of the complement component C3b was identified by indirect immunofluorescence assay (IFA). Additional specimens were incubated with autologous serum fixed in formalin, and their architecture was examined by hematoxylin and eosin (H&E) staining.

RESULTS

For 79% of UC patients, autologous serum caused C3b staining along the colonic epithelium. Recombinant hTM5 or anti-hTM5 monoclonal antibody blocked serum-induced C3b deposition. Immunoglobulin G (IgG) antibody and affinity-purified anti-hTM5 IgG antibody from UC sera with complement caused C3b deposition, indicating specificity of hTM5 as an autoantigen. When analyzed by H&E staining, sera obtained from 71% of UC patients caused a significant loss of epithelium. This process was inhibited by Fc fragments, indicating that it is complement mediated. With medium, normal, or CD serum, there was no C3b deposition or morphological changes of the colonic epithelium, indicating disease specificity. The ileal mucosa was not affected by UC sera, suggesting specificity for the colon. In UC mucosa, expression of hTM5 increased.

CONCLUSIONS

hTM5 acts as an autoantigen in UC. hTM5-specific IgG autoantibody in sera from UC patients induces C3b deposition and destruction of colonic epithelial cells, suggesting a direct pathogenic effect. If used as a diagnostic test to distinguish UC from CD, IFA would have 79% sensitivity and 100% specificity. Development of blocking antibodies may lead to novel therapies.

The new salicylate derivative UR-1505 modulates the Th2/humoral response in a dextran sodium sulphate model of colitis that resembles ulcerative colitis

The aim of the present study was to evaluate the inmunomodulatory effects of UR-1505, a new salicylate derivative, on the T helper (Th)2/humoral response produced during dextran sodium sulfate (DSS)-induced rat colitis. In the in vitro studies, UR-1505 (300 microM) inhibited both the production of interleukin (IL)-10 and IL-5 in concanavalin A (Con A)-activated splenocytes and the production of immunoglobulin (Ig) G and IgA by B-lymphocytes. However, in contrast to the in vitro results, the administration of UR-1505 (10 and 30 mg/kg per day) to rats with established DSS-colitis enhanced both IL-10 and IgA production, whereas it inhibited IgG production, thus ameliorating the intestinal inflammation.

Autoantibodies against human tropomyosin isoform 5 in ulcerative colitis destroys colonic epithelial cells through antibody and complement-mediated lysis

INTRODUCTION

Patients with ulcerative colitis (UC) have IgG1 antibodies in serum and colon against human tropomyosin isoform 5 (hTM5), a cytoskeletal microfilament protein found intracellularly and on the surface of colonic epithelial cells (EC). These antibodies may be pathogenic in UC.

METHODS

Sera from patients with UC (n=110) or Crohn's disease (CD) (n=50) and from healthy individuals (Hl) (n=30) were preincubated with recombinant hTM5 or bovine serum albumin (BSA), then cultured for 4h with (51)Cr-labelled colonic adenocarcinoma cells (LS180). Cytotoxicity was determined by (51)Cr release assay.

RESULTS

All serum samples lysed up to 36% of LS180 cells regardless of the source of the serum. However, adding hTM5 to UC, but not to CD or HI, sera reduced cytotoxicity by up to 75%. This hTM5-induced inhibition of cytotoxicity was found especially with sera from UC patients with active disease, and was found even after total colectomy. The hTM5-induced inhibition was mediated by purified IgG from UC sera. Complement was involved since hTM5-induced inhibition of cytotoxicity declined with either heat inactivation of the sera or premixing sera with Fc fragments.

CONCLUSIONS

This study shows that hTM5-specific IgG autoantibodies present in UC sera destroy LS180 cells by antibody and complement-mediated lysis. Such a phenomenon was not seen in CD or HI. This suggests an autoantigenic role of hTM5 and anti-hTM5 antibodies in the pathogenesis of UC. This observation may lead to novel diagnostic and therapeutic possibilities.

Autoimmunity against human tropomyosin isoforms in ulcerative colitis: localization of specific human tropomyosin isoforms in the intestine and extraintestinal organs

BACKGROUND

Tropomyosins (TMs) are microfilament cytoskeletal proteins, and 5 major human TM isoforms (hTM1-5) are described. hTMs, particularly isoform 5 (hTM5), is capable of inducing autoantibodies and T-cell response in ulcerative colitis (UC). However, cellular localization of hTM isoforms in the colon and in extraintestinal organs commonly involved in UC is unknown.

METHODS

Using isoform-specific monoclonal antibodies, we localized hTMs through immunoperoxidase assay in normal colon (n = 12), small intestine (n = 14), esophagus (n = 10), skin (n = 19), eye (n = 12), gallbladder (n = 16), liver, including bile duct at the porta hepatis (n = 4), lungs (n = 4), and pancreas (n = 4).

RESULTS

There is intense expression of hTM5, but not other isoforms, in the epithelium of the colon, gallbladder, and skin. In the eye, hTM5 is expressed only in the nonpigmented ciliary epithelium. Although extrahepatic and interlobar large ductal biliary epithelium was positive, bile canaliculi at the portal tract are negative. The immunoreactivity in epithelial cells from these organs is diffuse cytoplasmic and along the periphery. In colon epithelium, there is intense expression along basolateral areas and luminal (apical) surface. In the small intestinal epithelium, however, hTM5 expression is weak and distinctly different than in the colon. hTM5 was not detected in the squamous epithelium of the esophagus, although it was strongly positive in the skin. hTM1, hTM2, and hTM3 are localized predominantly in smooth muscle of the intestine and blood vessel wall but not the epithelium. HTM4 is localized in the endothelial cells and basement membrane of the colonic epithelium.

CONCLUSIONS

hTM5 is the predominant isoform in the epithelium of colon and extraintestinal organs commonly involved in UC. The unique expression of hTM5 may allow its interaction with effector immune cells involved in the immunopathogenesis of UC and its extraintestinal manifestations.

Systemic lupus erythematosus and inflammatory bowel disease

We hereby summarize a case reported by the authors, as well as all of the previously reported cases, of patients suffering from both systemic lupus erythematosus (SLE) and inflammatory bowel disease (IBD) that have been published in the English literature. In most cases, SLE was diagnosed prior to IBD, and the latter was of the ulcerative colitis subtype. Interestingly, the first disease diagnosed was almost never active at the time the second disease manifested itself. Patients with both diseases tended to have less photosensitivity, less arthritis, and less serositis than patients with SLE alone. There were no cases with neurological disorders or overt nephritis. All of these patients had anti-dsDNA and there was a tendency towards more anemia and thrombocytopenia. These patients had a relatively benign course with no flare-ups of lupus during follow-up and a favorable course of their bowel disease as well.

The B-cell system in inflammatory bowel disease

Secretory immunity is the best-defined part ot the mucosal immune system. This adaptive humoral defense mechanism depends on a fine-tuned cooperation between secretory epithelia and local plasma cells. Such mucosal immunocytes produce preferentially dimers and larger polymers of immunoglobulin A (collectively called pIgA), which contain J chain and therefore can bind to the epithelial secretory component (SC). This transmembrane glycoprotein functions as pIg receptor (pIgR) that also translocates pentameric IgM to the epithelial surface. B cells with a high level of J-chain expression and pIg-pIgR interactions at mucosal effector sites are thus necessary for the generation of secretory antibodies (SIgA and SIgM). Secretory antibodies perform immune exclusion in a first-line defense, thereby counteracting microbial colonization and mucosal penetration of soluble antigens. However, local production of pIgA is significantly down-regulated in inflammatory bowel disease (IBD), as revealed by strikingly decreased J-chain expression. Although the total increase of the immunocyte population in IBD lesions probably compensates for the relatively reduced pIgA production, decreased pIgR/SC expression in regenerating and dysplastic epithelium signifies that the SIgA system is topically deficient. There is, moreover, a significant shift from IgA2 to IgA1 production, the latter subclass being less resistant to proteolytic degradation. These changes--together with activation of mucosal macrophages and a dramatic increase of IgG-producing cells--may reflect local establishment of a second defense line which, however, is unsuccessful in its attempt to eliminate antigens derived from the indigenous microbial flora. Such a 'frustrated' local humoral immune system results in altered immunological homeostasis and jeopardized mucosal integrity. Complement activation observed in relation to epithelium-bound IgG1 in ulcerative colitis indicates, moreover, that the surface epithelium is subjected to immunological attack by an autoimmune reaction. These luminal deposits regularly contain terminal cytotoxic complement, and often also C3b as a sign of persistent activation. Comparison of identical twins, discordant with regard to ulcerative colitis, suggests that the markedly skewed local IgG1 response seen in this IBD entity may be genetically determined. The initial event(s) eliciting B-cell driven immunopathology in IBD remains unknown. Abrogation of oral tolerance to certain antigens from commensal bacteria has been suggested as a putative early mechanism, and lymphoid neogenesis and hyperplasia in the lesions most likely signify massive microbial overstimulation of the local B-cell system. Such ectopic lymphoid microcompartments may contribute substantially to the proinflammatory systemic-type of B-cell responses occurring in established IBD lesions.

HLA class-I-restricted and colon-specific cytotoxic T cells from lamina propria lymphocytes of patients with ulcerative colitis

We established cytotoxic T-lymphocyte (CTL) lines against colonic epithelial cell line from LPLs of patients with ulcerative colitis by continuous stimulation with human lymphocyte antigen A (HLA-A) matched colonic epithelial cell lines and clones from LPLs using polyclonal stimulation with phytohemagglutinin. The established CTL lines and clones showed cytotoxicity against HLA-A-matched colonic epithelial cell line but not against HLA-mismatched colonic epithelial cell lines, and HLA-A-matched lung and esophagus cell lines. The CTL response was HLA class I-restricted and mediated by CD8-positive T-lymphocytes. Moreover, the CTL line showed cytotoxicity against autologous B-LCLs pulsed with peptides extracted from HLA-A-matched colonic epithelial cell line but not against other organ-derived peptides pulsed and unpulsed autologous B-LCLs. CTL lines and clones established from LPLs of patients with ulcerative colitis showed colon-specific and HLA class I-restricted killing of human colonic epithelial cell line, suggesting that these CTLs may play a role in colonic epithelial cell damage in some patients with ulcerative colitis.

Loss of transforming growth factor beta signalling in the intestine contributes to tissue injury in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract caused by an abnormal and uncontrolled immune response to one or more normally occurring gut constituents.

AIM

Given the effects of transforming growth factor beta1 (TGF-beta1) on both the immune system and extracellular matrix, we postulated that alterations in TGF-beta signalling in intestinal epithelial cells may play an important role in the development of IBD.

METHODS

TGF-beta signalling was inactivated in mouse intestine by expressing a dominant negative mutant form of the TGF-beta type II receptor under the control of the mouse intestinal trefoil peptide (ITF)/TFF3 promoter. Transgenic mice (ITF-dnRII) developed spontaneous colitis presenting with diarrhoea, haematochezia, and anal prolapse when not maintained under specific pathogen free (SPF) conditions. Under SPF conditions we induced colitis by mixing dextran sodium sulphate (DSS) in drinking water to examine the significance of loss of TGF-beta signalling in the pathogenesis of IBD.

RESULTS

Transgenic mice showed increased susceptibility to DSS induced IBD, and elicited increased expression of major histocompatibility complex class II, generation of autoantibodies against intestinal goblet cells, and increased activity of matrix metalloproteinase in intestinal epithelial cells compared with wild-type littermates challenged with DSS.

CONCLUSIONS

Deficiency of TGF-beta signalling specifically in the intestine contributes to the development of IBD. Maintenance of TGF-beta signalling may be important in regulating immune homeostasis in the intestine

Oral administration of unmodified colonic but not small intestinal antigens protects rats from hapten-induced colitis

Colonic administration of a hapten, 2,4,6-trinitrobenzene sulphonic acid (TNBS) has been shown to induce colitis in rats. We are using this model to investigate the role of colonic antigens in the immunopathology. In this study, we show that colitis can be suppressed by oral administration of haptenized colonic antigens prior to the TNBS enema. Moreover, our data suggest that haptenization of the colonic antigens is not essential because oral feeding of non haptenized colonic antigens too protects rats from TNBS-induced colitis. Thus, unmodified colonic antigens may be involved in the induction of oral tolerance, and possibly in the pathogenesis in this model of colitis. Further, we show that the protective immunity or oral tolerance induced by non haptenized colonic antigens can be passively transferred to naïve rats by mesenteric T lymphocytes. Interestingly, oral feeding of small intestinal antigens, haptenized and non haptenized, does not protect rats from colitis, suggesting a specific role for colonic antigens. These data underscore the usefulness of this rat model in the identification of pathogenic antigens in colitis and in the development of therapeutic strategies based on oral tolerance.

Autoimmunity in ulcerative colitis (UC): a predominant colonic mucosal B cell response against human tropomyosin isoform 5

We set out to examine if the IgG-producing cells in the colonic mucosa in UC are committed to tropomyosin isoform 5 (hTM5), a putative autoantigen in UC. Lamina propria mononuclear cells (LPMC) were isolated from colonoscopic biopsy specimens from recto-sigmoid and proximal colon. Twenty-three patients with UC, eight with Crohn's colitis (CC), and 10 non-inflammatory bowel disease (non-IBD) controls were included. The ELISPOT assays were used to quantify lamina propria B cells producing total immunoglobulin (IgA, IgG, IgM), IgG, IgA, as well as IgG against hTM5 isoform. The median value of percentage of total IgG-producing lymphocytes was similar in UC (12%) and CC (11%), but was significantly (P < 0.0002) higher than non-IBD controls (6%). However, in UC, but not in CC and non-IBD, a large number of lamina propria B cells produced IgG against hTM5 (median values: UC 42%, CC 2.5%, non-IBD 0%). This difference in UC when compared with CC and non-IBD was highly significant (P < 0.00001). Twenty-one of 23 (91%) patients with UC had percentage of anti-hTM5 IgG-producing immunocytes more than 2 s. d. above the mean for non-UC patients. In UC but not in CC and non-IBD controls, the increased number of IgG-producing cells are largely committed to produce IgG against hTM5-related epitope(s).

Detection of anti-colon antibodies in inflammatory bowel disease using human cultured colonic cells

BACKGROUND

Investigation of anti-colon antibodies may be simplified if a sensitive method and homogeneous source of antigen were available.

AIMS

To examine the anti-colon antibody response using human colonic carcinoma cell lines as antigen.

SUBJECTS

Patients with inflammatory bowel disease and other gastrointestinal disorders and healthy controls were studied.

METHODS

Comparative enzyme linked immunosorbent assays (ELISAs) were performed to assess the value of whole Caco-2, HT-29, and LS-180 cells as antigen. The antigenic determinants of the immune response were characterised by western blot analysis.

RESULTS

Sera demonstrated immunoreactivity against each of the cell lines, but different epitopes were recognised. Applying whole Caco-2 cells as antigen in an ELISA, the prevalence of anti-colon antibodies was significantly greater in patients with ulcerative colitis (36%) than Crohn's disease (13%), other gastrointestinal disorders (13%) and healthy controls (0) (p<0. 05). The immune response was not associated with one predominant antigen.

CONCLUSIONS

Fixed whole cell ELISA is a simple and feasible method for studying the anti-colon antibody response. This response is non-specific, being directed against multiple antigens, and is likely to be an epiphenomenon of inflammatory bowel disease, more so for ulcerative colitis than Crohn's disease.

Antinuclear autoantibodies in patients with inflammatory bowel disease. High prevalence in first-degree relatives

Crohn's disease and ulcerative colitis show a familial aggregation. The role of antinuclear autoantibodies, which occur in both diseases, remains to be defined. In 76 patients with Crohn's disease, 61 patients with ulcerative colitis, 105 first-degree relatives of patients with Crohn's disease, 101 first-degree relatives of patients with ulcerative colitis, and 40 healthy unrelated controls antinuclear autoantibodies were detected by indirect immunofluorescence. Existence of autoantibodies was correlated with clinical features. Eighteen percent of patients with Crohn's disease (14/76), 43% of patients with ulcerative colitis (26/61), 13% of relatives of patients with Crohn's disease (14/105), 24% of relatives of ulcerative colitis patients (24/101), and 2% of the healthy controls (1/40) were positive for antinuclear autoantibodies. The difference between controls and patients and the first-degree relatives of patients with ulcerative colitis, respectively, was statistically significant (P < or = 0.0144). In ulcerative colitis, the existence of antinuclear autoantibodies was negatively correlated with immunosuppressive therapy or extraintestinal manifestations (P = 0.0004 and 0.0273, respectively). Antinuclear autoantibodies may represent a factor disposing to the development of ulcerative colitis.

The serum factor from patients with ulcerative colitis that induces T cell proliferation in the mouse thymus is interleukin-7

The disturbance of immune regulatory T cells is related to the pathogenesis of ulcerative colitis. Here we demonstrated and characterized the serum factor from ulcerative colitis patients that induced proliferation of intrathymic T cells. The factor isolated from the patient sera by a combination of gel filtration and anion-exchange chromatography induced proliferation of CD4+CD8- intrathymic T cells in the organ-cultured embryonic mouse thymus. Purification and amino acid sequence analysis of the serum factor demonstrated that the N-terminal 12 sequence was homologous to that of interleukin-7. SDS-PAGE and Western blot confirmed that purified serum factor was interleukin-7. Enzyme immunoassay demonstrated that the serum interleukin-7 concentration was significantly increased in the patients. PCR and Southern blot hybridization demonstrated that interleukin-7 mRNA expression was increased in the thymus tissues from patients but decreased in the colonic mucosa. Since interleukin-7 is a crucial cytokine for proliferation and differentiation of T cells in the thymus, the present study indicates that interleukin-7 may contribute to the disturbance of immune regulatory T cells in ulcerative colitis.

Rheumatoid arthritis associated with ulcerative colitis

This report describes a 58-year-old man with rheumatoid arthritis (RA) and interstitial pneumonia who suffered from low-grade fever, abdominal pain, and bloody diarrhea 16 months after the diagnosis of RA. Ulcerative colitis (UC) was diagnosed, based on endoscopic and histological findings. RA associated with UC is rare and the underlying mechanism is unknown. We discuss here whether vasculitis and HLA class may play some role in the association of RA with UC.

Inflammatory bowel disease in C.B-17 scid mice reconstituted with the CD45RBhigh subset of CD4+ T cells

Chronic inflammation developed spontaneously in the large intestine of C.B-17 scid mice restored with the CD45RBhigh subset of CD4+ T cells obtained from normal BALB/c mice. The inflammation, which extended diffusely from the cecum to the rectum, was localized to the lamina propria of mildly affected mice but became transmural in severely affected mice. Immunohistochemical and flow cytometric analyses showed that the inflammatory infiltrate contained numerous macrophages accompanied by moderate numbers of activated CD4+ lymphocytes. Some mice also had scattered multinucleated giant cells. Mucin depletion and epithelial hyperplasia resulting in glandular elongation and mucosal thickening were also consistently seen. Less frequent findings included ulceration with fibrosis, crypt abscesses, crypt loss, and granulomatous inflammation. Immunofluorescent analysis of inflamed large intestinal sections demonstrated increased epithelial expression of major histocompatibility class II antigens. The changes in the large intestine of these mice are similar to those seen in patients with idiopathic inflammatory bowel disease (Crohn's disease and ulcerative colitis). This murine model may be useful for studying mucosal immunoregulation as it relates to the pathogenesis and treatment of chronic inflammatory bowel diseases in the large intestine of human patients.

Production of immunoglobulin G and G1 antibodies to cytoskeletal protein by lamina propria cells in ulcerative colitis

BACKGROUND & AIMS

Recent studies suggest an autoantigenic role for tropomyosin-related protein(s) in ulcerative colitis (UC). This study examined whether immunoglobulin G and G1 subclass antibodies against tropomyosins are produced spontaneously by the lamina propria mononuclear cells (LPMCs) that infiltrate the inflamed UC tissue.

METHODS

LPMCs were isolated from colonic biopsy specimens from 29 patients with UC, 15 with colonic Crohn's disease (CD), and 13 with non-inflammatory bowel disease (IBD). The autologous peripheral blood mononuclear cells (PBMCs) were obtained. Cells were cultured in vitro and unstimulated for 10 days. Spontaneous production of immunoglobulin G and G1 antibodies against tropomyosins was measured by enzyme-linked immunosorbent assays using highly enriched tropomyosins from skeletal muscle and colonic mucosa.

RESULTS

The total immunoglobulin G produced by LPMCs from both patients with UC and CD was comparable but higher than from patients with non-IBD (P < 0.05). However, immunoglobulin G antibodies to tropomyosins were higher in patients with UC than in patients with CD (P < 0.04) and non-IBD (P < 0.02). LPMCs from patients with symptomatic UC produced higher immunoglobulin G antibodies to tropomyosins than patients with UC in remission (P < 0.03), symptomatic CD (P < 0.04), and non-IBD (P < 0.02). Immunoglobulin G antibodies to tropomyosins predominantly belonged to immunoglobulin G1 subclass. The autologous PBMCs showed comparable results.

CONCLUSIONS

Immunoglobulin G antibodies predominantly belonging to immunoglobulin G1 subclass and reactive against tropomyosin-related protein(s) are spontaneously produced by LPMCs from the colonic mucosa in patients with UC.

Expression of a unique protein on colon cancer cells that reacts with a novel monoclonal antibody and ulcerative colitis serum

We earlier developed a MoAb, 7E12H12 (IgM isotype), against a protein present in normal colonic epithelial cells. To examine if 7E12H12-reactive protein is expressed in colon cancer cells and is recognized by ulcerative colitis (UC)-associated autoantibody, we investigated several colon cancer cell lines. 7E12H12 reactivity against the cells was examined by indirect immunofluorescence assay and whole cell ELISA against six colon cancer cell lines HT-29, LoVo, COLO 205, DLD-1, LS 180 and SW 1116. A competitive ELISA was developed using 7E12H12 MoAb and patients' serum to examine the cross-reactive antibodies in the serum. Among the six colon cancer cell lines only LS 180, DLD-1 and SW 1116 reacted with 7E12H12 MoAb, while others did not. The mean (+/- s.e.m.) inhibition of the binding of 7E12H12 MoAb to LS 180 cells by UC serum (n = 51) was 42 +/- 2.1%, whereas in normal subjects (n = 17) it was 14 +/- 2.6%, in Crohn's disease (n = 19) it was 15.3 +/- 2.5%, in infectious diarrhoea (n = 10) it was 11% +/- 3%, and in systemic lupus erythematosus (n = 10) it was 2% +/- 0.6%. The inhibition by the UC group was significantly (P < 0.001 - < 0.0001) higher than any of the non-UC groups, and this inhibition was mainly by IgG1 antibody. The protein in the specific colon cancer cells recognized by the 7E12H12 MoAb cross-reacts with UC-IgG1 antibody and may provide an in vitro system to examine the autoimmune mechanisms in UC.

Immunoglobulin G subclass distribution of human anticolon antibodies in ulcerative colitis

Immunoglobulin G (IgG) subclasses of anticolon antibodies were studied in patients with ulcerative colitis (UC) using enzyme-linked immunosorbent assay (ELISA). The concentrations of total serum IgG subclasses were also measured by ELISA. The values for total serum IgG subclasses in patients with UC were not significantly different from those in normal controls, while the ratio of IgG1 to IgG2 in the patients was significantly higher than that in normal controls. All four IgG subclasses of autoantibodies were demonstrated in the sera of the patients. IgG4 anticolon antibodies were detected most frequently (15 out of 18 patients, 83%). IgG2 was the next most prevalent (9 of 18 patients, 50%). The activity of anticolon antibodies in each subclass did not correlate with the concentration of the corresponding serum IgG subclass. Seven cell lines producing anticolon antibodies were obtained from the colonic mucosa of the patients by Epstein-Barr virus (EBV) transformation. IgG subclasses of anticolon antibodies secreted by these cell lines were also varied. IgG4 subclass was secreted by three EBV transformed cell lines, all of which produced IgG4 anticolon antibodies. These results suggest that all four different IgG subclasses could respond to the colon antigens and that various antigens in colonic mucosa or lumen may contribute to the induction of those autoantibodies. In addition, the prominence of IgG4 anticolon antibodies may support the pathogenic role of this subclass in UC as in other autoimmune diseases.

Autoimmunity in ulcerative colitis: tropomyosin is not the major antigenic determinant of the Das monoclonal antibody, 7E12H12

Ulcerative colitis (UC) has a proposed autoimmune pathogenesis. A 40-kD antigen (P40) has been isolated from UC colon, bound to immunoglobulin. Tropomyosin has been reported as the target antigen of a MoAb (7E12H12) raised against P40. We set out to investigate whether tropomyosin is the major antigenic determinant for 7E12H12. Formalin-fixed, paraffin-processed and cryostat sections of fresh frozen colon from patients with UC, Crohn's disease and normals, were immunostained with 7E12H12 and commercial anti-tropomyosin antibodies. In addition, the immunoreactivity of 7E12H12 with cytoskeletal components was examined on human endothelial cells (HUVEC) using anti-tropomyosin as a positive control. Con-focal microscopy was used to determine the subcellular localization of signal. An extract of total colonic protein from UC colon was prepared. Using a combination of Western and immunoblotting (dot-blots), the immunoreactivities of both tropomyosin (porcine and chicken) and colon protein extract with either 7E12H12 or commercial anti-tropomyosin were examined. Immunocytochemically, 7E12H12 localized to the apical and basolateral regions of plasma membrane, and to the supranuclear cytoplasm in colonic epithelium. Using anti-tropomyosin antibody it was not possible to identify the cytoskeleton in colonic epithelium. Cytoskeletal components were identifiable in HUVEC cultures with anti-tropomyosin antibody but not with 7E12H12. P40 antigen was identified in the colon protein extract by immunoblotting with 7E12H12. There was clear immunoreactivity between anti-tropomyosin antibody and both chicken and porcine tropomyosin, and the colon protein extract. 7E12H12 did not bind to either chicken or porcine tropomyosin in appropriately controlled systems. We conclude that the pattern of immunostaining with 7E12H12 is not cytoskeletal, and there is no reactivity in immunoblots, between tropomyosin and 7E12H12. Tropomyosin is not the major target antigen of this antibody in ulcerative colitis.

Circulating immunoglobulin G1 antibody in patients with ulcerative colitis against the colonic epithelial protein detected by a novel monoclonal antibody

Autoimmunity has been implicated in the pathogenesis of ulcerative colitis (UC). Several studies have shown amplified immunoglobulin G1 (IgG1) antibody response in UC; however the immunoreactive antigen(s) is unknown. To study this antigen(s), mucosal colonic extract was prepared by sonication, ultracentrifugation followed by ion exchange chromatography in fast protein liquid chromatography. The fraction (enriched colonic peptide), that was most reactive to a novel monoclonal antibody, 7E12H12 (IgM isotype), was isolated and used to examine the immunoreactivity against the patients' serum samples. Two hundred and thirteen coded samples from 111 patients with UC (symptomatic and untreated (63), symptomatic and treated (26), remission (22)); 47 with Crohn's disease (CD) (40 were symptomatic and untreated, and 30 had colonic disease); 29 with acute diarrhoea caused by specific pathogen(s); 10 with systemic lupus erythematosus, and 16 normal subjects were examined against the enriched colonic peptide by IgG subtype specific enzyme linked immunosorbent assays (ELISAs). Total IgG antibody reactivity was significantly (p < 0.01) higher only in symptomatic and untreated UC patients compared with each of the non-UC group, but the sensitivity was only 50%. IgG2 and IgG3 reactivities were not different among various groups. The IgG1 antibody reactivity against the enriched colonic peptide, however, differentiated UC patients from CD and each of the other non-UC groups. Seventy nine per cent of the patients with UC, treated or untreated, symptomatic or in remission, had significantly (p < 0.0001) higher IgG1 antibody against the enriched colonic peptide when compared with each of the other non-UC groups. Only 12% of CD serum samples and none of the other control serum samples reacted. Using purified serum IgG1 and 7E12H12-IgM, by 7E12H12 reactive peptide indeed reacts with UC-IgG1 antibody but not with control IgG1.

Systemic lupus erythematosus in association with ulcerative colitis: related autoimmune diseases

We report a patient who developed urticaria, angio-oedema and polyarthropathy secondary to the hypocomplementaemic urticarial vasculitis syndrome, a year prior to the onset of ulcerative colitis. Ten years later, primary sclerosing cholangitis and the antiphospholipid syndrome developed concomitantly. We believe this patient represents only the second reported case of idiopathic systemic lupus erythematosus (SLE) occurring in association with ulcerative colitis.

Enzyme linked immunosorbent assay (ELISA) and immunoprecipitation studies on anti-goblet cell antibody using a mucin producing cell line in patients with inflammatory bowel disease

Circulating anti-goblet cell antibody and its corresponding antigen in patients with inflammatory bowel disease were investigated. Anti-goblet cell antibody in the serum was examined by immunocytochemistry and enzyme linked immunosorbent assay (ELISA), using a colonic cancer cell line, HT29-18-N2, which differentiates into intestinal goblet cells. The frequencies of anti-goblet cell antibody detected by immunocytochemistry were 14 in 48 patients with ulcerative colitis (29%) and five in 15 patients with Crohn's disease (33%). By ELISA, the frequencies of anti-goblet cell antibody were 38% in ulcerative colitis and 33% in Crohn's disease. This antibody did not relate directly to anti-neutrophil cytoplasmic antibodies (ANCA), although the serum samples positive for anti-goblet cell antibody were commonly positive for ANCA in ulcerative colitis. Immunoprecipitation and SDS polyacrylamide gel electrophoresis (PAGE) study showed that the antibody in the ELISA positive serum samples recognised a > 200 kD goblet cell antigen, which remained unchanged after reduction, indicating that it consists of single chain polypeptides. These results suggest that there is a subgroup of inflammatory bowel disease that has circulating anti-goblet cell antibody reactive with a > 200 kD antigen. The antibody detected by newly established ELISA will be a disease marker for this group and the identification of the corresponding antigens may be important for the understanding of the underlying immune abnormalities.

Ulcerative colitis-like disease in mice with a disrupted interleukin-2 gene

Mice deficient for interleukin-2 develop normally during the first 3-4 weeks of age. However, later on they become severely compromised, and about 50% of the animals die between 4 and 9 weeks after birth. Of the remaining mice, 100% develop an inflammatory bowel disease with striking clinical and histological similarity to ulcerative colitis in humans. The alterations of the immune system are characterized by a high number of activated T and B cells, elevated immunoglobulin secretion, anti-colon antibodies, and aberrant expression of class II major histocompatibility complex molecules. The data provide evidence for a primary role of the immune system in the etiology of ulcerative colitis and strongly suggest that the disease results from an abnormal immune response to a normal antigenic stimulus.

Immunohistochemical study of thymic B cells in myasthenia gravis and ulcerative colitis

The phenotypes of B cells and dendritic cells in human thymus were examined immunohistochemically using various monoclonal antibodies. Normal thymus contained a few B lymphocytes recognized by CD19, CD20, CD22, L26 and LN-2, which were localized in the medulla. These B cells were negative for LN-1, L30 and CD11c (Leu M5). Activated B cells recognized by CD23 (B6) and L29 antibodies were not present in normal thymus. Dendritic cells stained by CD11c were weakly positive for L26 and CD20. There was no difference in the distribution of dendritic cells between normal thymus and thymus from the patients. In the thymus from patients with myasthenia gravis, numerous B cells were demonstrated in the medullary area and lymphoid follicles. Activated B cells were seen mainly in the germinal center of lymphoid follicles and were scarce in the medulla. Many B cells were also found in the medulla and lymphoid follicles of the thymus from patients with ulcerative colitis. However most of those B cells were not activated, even in the lymphoid follicles. These results suggest that thymic B cells may contribute to the induction of immune abnormalities in patients with myasthenia gravis and those with ulcerative colitis, however, the mechanisms by which thymic B cells participate in the pathogenesis of these two diseases would be different.

Interleukin 2 and interferon-gamma augment anticolon antibody dependent cellular cytotoxicity in ulcerative colitis

In vitro effects of cytokines and therapeutic drugs on antibody dependent cellular cytotoxicity (ADCC) mediated by anticolon antibody were investigated in serum samples from patients with ulcerative colitis. A 51Cr release assay was used to examine ADCC activity with the colon cancer cell line, colo 205, as the target and peripheral blood mononuclear cells as the effector. High ADCC activity was shown in 13 of 32 (41%) patients with ulcerative colitis. This ADCC activity was inhibited by protein A treatment of the serum samples. Interleukin 2 (IL2) activated effector cells could enhance ADCC activity, but interferon-gamma (IFN-gamma) or tumour necrosis factor-alpha (TNF-alpha) had no effect on the cytotoxic activity of effector cells. Treatment of target cells with IFN-gamma increased the vulnerability of these cells to ADCC with a large increase of intercellular adhesion molecule-1 (ICAM-1) expression on their surface. Monoclonal antibodies to ICAM-1 inhibited this IFN-gamma enhanced ADCC activity. Interestingly, prednisolone (PSL) reduced ADCC activity, but sulphasalazine (SASP) or 5-aminosalicylic acid (5-ASA) did not. These results suggest that IL2 and IFN-gamma could enhance colonic epithelial cell injury mediated by the ADCC mechanism in ulcerative colitis and that ADCC enhanced by cytokines is restored by PSL treatment.

Epithelial deposits of immunoglobulin G1 and activated complement colocalise with the M(r) 40 kD putative autoantigen in ulcerative colitis

The intestinal expression pattern and general tissue distribution of the M(r) 40 kD putative epithelial autoantigen in ulcerative colitis were re-examined by in situ two and three colour immunofluorescence staining including the murine monoclonal antibody 7E12H12. The intestinal distribution was also compared with the epithelial codeposition of IgG1 and activated complement (C3b and terminal complement complex) seen selectively in ulcerative colitis. The M(r) 40 kD antigen was found for the first time in goblet cells of normal terminal ileum and proximal colon but not in rectal goblet cells. By contrast, colonic enterocytes expressed this antigen apically with increasing intensity in a distal direction, expanding to intense cytoplasmic expression in rectal enterocytes. The antigen was also expressed by the epithelium of the fallopian tubes, major bile ducts, gall bladder, and epidermis but not by proximal gastrointestinal tract epithelium or 13 other extra-gastrointestinal organs. Activated complement and IgG1 often colocalised with the M, 40 kD antigen apically on the surface epithelium in active ulcerative colitis but not in Crohn's disease. Our results support the idea that an autoimmune response to this antigen, leading to complement activation mediated by IgG1, is a possible pathogenetic mechanism for epithelial damage and persistent inflammation in ulcerative colitis.

Detection of a circulating antibody against a peptide epitope on a mucin core protein, MUC1, in ulcerative colitis

This study aims at clarifying whether the humoral immune response to the tandem repeat domain of MUC1 can be induced or not in vivo. The expression of MUC1 mRNA in the colon was revealed by Northern blot analysis, and cDNA cloning of an extracellular tandemly repeated domain of MUC1 was then performed to prepare the recombinant MUC1 protein. A cDNA clone coding for ten repeat domains was ligated into an expression vector in prokaryotes, resulting in a recombinant protein which could react with the MAb MUSE11 against an adenocarcinoma-associated antigen whose epitope has been shown to be localized in the tandem repeat domain on MUC1. The reactivity of sera from patients with ulcerative colitis with the recombinant protein was evaluated by SDS-PAGE and Western blot analysis to detect the antibodies against this tandem repeat domain. Five out of 19 serum samples tested positive, and these reactions were totally inhibited by MAb MUSE11, suggesting that the epitope recognized by these antibodies in sera is almost identical to that recognized by MAb MUSE11. The data represent the first demonstration of antibody production against a peptide epitope of the tandem repeat domain of MUC1.

Inflammatory bowel disease. Part I: Nature and pathogenesis

Once regarded as medical curiosities, ulcerative colitis and Crohn's disease have achieved a remarkable change in status recently and today are among the more compelling of all human illnesses. The cause(s) of inflammatory bowel disease (IBD) are not known. Genetic, environmental, microbial, and immunologic factors are involved, but the precise mechanisms are obscure. The incidence of ulcerative colitis is relatively stable, while Crohn's disease continues to increase in frequency. In 10% to 15% of patients, it is hard to differentiate between ulcerative colitis and Crohn's colitis; however, problems with diagnosis usually resolve with time and repeated examinations. In part I of his two-part monograph on IBD, Dr. Kirsner addresses the nature and pathogenesis of the disease. Increased study of ulcerative colitis and Crohn's disease in recent years has generated new knowledge regarding their etiology. Part I focuses on microbial, immunologic, and genetic mechanisms and the inflammatory processes involved in the disease. In part II, which will be presented in next month's issue of Disease-a-Month, Dr. Kirsner deals with the clinical features, course, and management of IBD, based on the author's 55 years of experience with these problems and supplemented by critical examination of the recent (1988-1990) literature. Particular attention is directed to the symptoms and physical findings of ulcerative colitis and Crohn's disease, the laboratory, radiologic, endoscopic, and pathologic features, and the many systemic complications. The IBDs are mimicked by several enterocolonic infections and other conditions, making differential diagnosis necessary. Inflammatory bowel disease in children and the elderly conforms to conventional clinical patterns modified by the health circumstances of the respective age groups. Because the cause of IBD has not been established, current medical therapy is facilitative and supportive rather than curative. The principles of medical treatment are approximately the same for ulcerative colitis and Crohn's disease. Treatment emphasizes a program rather than a drug and also considers the individuality of the therapeutic response. A clearer understanding of dietary and nutritional needs, including hyperalimentation and electrolyte and fluid balance, aids treatment. Antidiarrheal and antispasmodic preparations and sedatives are prescribed for symptom relief. The bowel inflammation is controlled with sulfasalazine or the newer 5-amino salicylic acid (5-ASA) compounds, antibacterial drugs for complications of Crohn's disease and IBD, adrenocortical steroids, and the immunosuppressive compounds 6-mercaptopurine (6-MP), azathioprine, and cyclosporine, as determined in each patient. The surgical procedures available for treatment of ulcerative colitis include total proctocolectomy and ileostomy or ileoanal anastomosis.(ABSTRACT TRUNCATED AT 400 WORDS)