Antibody testing for ulcerative colitis--more letters?

The presence of perinuclear antineutrophil cytoplasmic antibodies (P-ANCAs) and antibodies against cathepsin G, a target antigen for P-ANCAs, was determined in the sera of patients with ulcerative colitis (UC), relative to endoscopic severity and disease activity. P-ANCAs were detected by indirect immunofluorescent assay on ethanol-fixed human neutrophils. Antibodies to cathepsin G were detected by ELISA and Western blotting. P-ANCAs were detected by immunofluorescent assay in 62.5% of 32 patients with active UC. Anti–cathepsin G antibodies were detected in 40.6% of 32 patients with active UC, and their prevalence was significantly higher in patients with severe colitis, as determined by endoscopy, than in those with mild or moderate colitis. The prevalence and titers of anti–cathepsin G antibodies were significantly higher during the active phase of the disease than during the inactive phase.     

Autoantibodies to neutrophil cytoplasmic (ANCA) and endothelial cell surface antigens (AECA) in chronic inflammatory bowel disease

Sera from 103 patients with chronic inflammatory bowel disease (IBD) were tested prospectively for antibodies against neutrophil cytoplasmic antigens (anti-neutrophil cytoplasm antibodies, ANCA) and endothelial cell surface antigens (anti-endothelial cell antibodies, AECA) by indirect immunofluorescence (IIF) and assays based on whole fixed neutrophils, purified neutrophil enzyme substrates and human umbilical vein endothelial cells. Using IIF, ANCA were found in 26 IBD sera (25%) and in none of 51 controls. Twenty-two positive sera (85%) were from patients with ulcerative colitis (UC). The pattern of distribution of immunofluorescence was always perinuclear (P-ANCA). A majority of UC patients positive for these autoantibodies (68%) had active colitis, but none had evidence of vasculitis. Using a whole neutrophil ELISA, binding was demonstrable in 73% of UC sera compared to 27% of Crohn's (CD) sera and only 4% of controls. Unlike vasculitis sera, UC sera with P-ANCA did not bind strongly to myeloperoxidase (MPO). Forty-five per cent of IBD sera tested positive for IgG AECA in an endothelial cell ELISA, compared to seven of 51 (14%) controls. Binding correlated with both active and extensive colitis. A type of P-ANCA, in most cases distinct from MPO-specific P-ANCA observed in vasculitis, is detected in a significant proportion of patients with UC, but rarely Crohn's colitis and therefore may be of differential diagnostic value. IgG AECA are also frequent in CIBD sera but are less disease specific than ANCA. (Aust NZ J Med 1992; 22: 652ndash;659.)     

High frequency of antigliadin antibodies and absence of antireticulin and antiendomysium antibodies in patients with ulcerative colitis

Several authors have described an association between celiac disease (CD) and ulcerative colitis (UC), but this has not yet been established. The aim of our study was to examine the frequency of antigliadin antibodies (AGA), antireticulin antibodies (ARA) and antiendomysium (AEM) antibodies in the sera of patients with UC (n = 50), and to evaluate their correlation with clinical variables. Sixteen patients with irritable bowel syndrome (IBS) and 37 healthy individuals served as controls. An enzyme-linked immunosorbent assay was used for the detection of IgA- and IgG-type AGA. IgG-type ARA were determined by an indirect immunofluorescence assay (IIF) using rat kidney, liver, and stomach as antigen substrates. IgA-type AEM antibodies were measured by IIF, using cryostat sections from human umbilical cord. Seventeen of the 50 patients with UC (34%) were positive for IgA- or/and IgG-type AGA. There was no correlation between the presence of AGA and the duration or extent of the disease, or disease activity. However, 5 patients with both IgA- and IgG-types of AGA had extensive colitis. Only 2 controls (4%) were positive for IgG-AGA. ARA and AEM were not detected in any individuals studied. Since the ARA and AEM test results were negative, we conclude that none of the UC patients in this series had CD. (Received Feb. 10, 1998; accepted July 30, 1998)     

Update on Anti-Saccharomyces cerevisiae antibodies, anti-nuclear associated anti-neutrophil antibodies and antibodies to exocrine pancreas detected by indirect immunofluorescence as biomarkers in chronic inflammatory bowel diseases： Results of a multicenter study

AIM: Anti-Saccharomyces cerevisiae antibodies (ASCA), anti-nuclear associated anti-neutrophil antibodies (NANA) and antibodies to exocrine pancreas (PAB), are serological tools for discriminating Crohn’s disease (CrD) and ulcerative colitis (UC). Like CrD, coeliac disease (CoD) is an inflammatory bowel disease (IBD) associated with (auto) antibodies. Performing a multicenter study we primarily aimed to determine the performance of ASCA, NANA and PAB tests for IBD diagnosis in children and adults, and secondarily to evaluate the prevalence of these markers in CoD. METHODS: Sera of 109 patients with CrD, 78 with UC, 45 with CoD and 50 healthy blood donors were retrospectively included. ASCA, NANA and PAB were detected by indirect immunofluorescence (IIF). RESULTS: ASCA /NANA- profile displayed a positive predictive value of 94.2% for CrD. Detection of ASCA was correlated with a more severe clinical profile of CrD and treatment of the disease did not influence their serum levels. ASCA positivity was found in 37.9% of active CoD.PAB were found in 36.7% CrD and 13.3% CoD patients and were not correlated with clinical features of CrD, except with an early onset of the disease. Fifteen CrD patients were ASCA negative and PAB positive. CONCLUSION: ASCA and PAB detected by IIF are specific markers for CrD although their presence does not rule out a possible active CoD. The combination of ASCA, NANA and PAB tests improves the sensitivity of immunological markers for CrD. Repeating ASCA, NANA, and PAB testing during the course of CrD has no clinical value.     

Antineutrophil cytoplasmic antibodies in Japanese patients with inflammatory bowel disease: prevalence and recognition of putative antigens

OBJECTIVE: Our aim was to investigate the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in Japanese patients with ulcerative colitis (UC) and Crohn's disease (CD), and the putative antigens recognized by perinuclear staining pattern ANCA (p-ANCA)-positive sera. METHODS: Sera from UC (n = 52) and CD (n = 43) patients, and from healthy controls (n = 74) were studied. The indirect immunofluorescence (IIF) method was used for the detection of ANCA and its binding pattern. p-ANCA-positive sera were studied further for putative antigens. ELISAs using lactoferrin (Lf), myeloperoxidase (MPO), and cathepsin G (Cat G) as antigens were performed. RESULTS: ANCA was positive in 40 of the 52 (76.9%) UC (p-ANCA in 33) and in 32 of the 43 (74.4%) CD (p-ANCA in 31) patients. UC and CD patients showed significantly higher titers of p-ANCA than controls; however, no significant difference was observed between UC and CD. In UC, 23, 17, and nine of the 33 patients with p-ANCA-positive sera showed reactivity with Lf, MPO, and Cat-G, respectively. In CD, 21, 20, and 11 of the 31 patients with p-ANCA-positive sera showed reactivity with Lf, MPO, and Cat-G, respectively. Fourteen of the UC and six of the CD patients showed reactivity with two different antigens, and seven of the UC and 11 of the CD patients showed reactivity with all three antigens. The presence of anti-Lf and anti-MPO antibodies was further confirmed by Western blotting. CONCLUSIONS: ANCA is useful in distinguishing patients with IBD from normal subjects but is not sufficient for the differential diagnosis of CD and UC. p-ANCA reactivity might be derived from the recognition of heterogeneous neutrophil-associated antigens.     

Anti-neutrophil cytoplasmic antibodies in patients with chronic liver diseases: prevalence, antigen specificity and predictive value for diagnosis of autoimmune liver disease. Swedish Internal Medicine Liver Club (SILK)

BACKGROUND: Anti-neutrophil cytoplasmic antibodies (ANCA) against proteinase 3 are diagnostic of Wegener's granulomatosis, but ANCA occur also in patients with other inflammatory disorders, such as ulcerative colitis, primary sclerosing cholangitis (PSC) and autoimmune hepatitis. As their predictive value for autoimmune liver disease remains unknown, we analysed the prevalence and antigen specificity of ANCA in patients with various chronic liver diseases (CLD). METHODS: We studied sera from 100 patients with primary biliary cirrhosis (PBC), from 76 with PSC and from 279 with various CLD, consecutively drawn during a 5-year period at the time of liver biopsy. The ANCA were detected by indirect immunofluorescence (IIF) while the antigen specificity was characterized by ELISA by using lactoferrin, neutrophil elastase, cathepsin G and BPI (bactericidal/permeability increasing protein) as antigens. RESULTS: In PBC, ANCA were detected by IIF in 39 patients (39%). The antigen reactivity by ELISA was lactoferrin in seven, elastase in 15, BPI in 20 and cathepsin G in four patients. Four patients had reactivity against more than one antigen. In PSC, IIF demonstrated ANCA in 49 patients (65%). The antigen reactivity was lactoferrin in 17, elastase in 14, BPI in 20 and cathepsin G in four patients. Twelve patients showed reactivity against more than one antigen. In CLD, ANCA were observed in sera from 55 patients (20%). Nineteen of 45 patients (42%) with autoimmune liver disease were ANCA positive versus 36/234 (15%) with non-autoimmune liver disease (P = 0.0002). Among IIF-positive patients, antibody reactivity against lactoferrin was noted in 14, elastase in 28, BPI in 25 and cathepsin G in five patients. Twenty-one patients had reactivity against more than one antigen. Elastase and BPI antibodies occurred more frequently in patients with autoimmune compared to non-autoimmune liver disease (P < 0.01). CONCLUSIONS: Anti-neutrophil cytoplasmic antibodies are prevalent in patients with chronic liver diseases, but although they occur more frequently in patients with autoimmune liver disease their specificity and sensitivity for autoimmune liver disease is low. The predominant antigens are lactoferrin, elastase and BPI, but the correlation between IIF findings and ELISA reactivity against these antigens is weak.     

Bactericidal/permeability-increasing protein and cathepsin G are the major antigenic targets of antineutrophil cytoplasmic autoantibodies in systemic sclerosis

OBJECTIVE: To study the prevalence and antigenic specificity of antineutrophil cytoplasmic autoantibodies (ANCA) in patients with systemic sclerosis (SSc). METHODS: Sera from 68 patients with SSc were screened for ANCA by indirect immunofluorescence (IIF) assay and for antibodies to myeloperoxidase (MPO) by ELISA. All sera positive for ANCA on IIF were analyzed for reactivity against antigenic targets other than MPO [bactericidal/permeability-increasing protein (BPI), cathepsin G, lysozyme, elastase, PR3, and lactoferrin]. Twenty-three sera negative for ANCA were also tested for antibodies to BPI and cathepsin G using ELISA. RESULTS: The study included 33 patients with diffuse and 35 with limited SSc. ANCA was detected in 24 of the 68 sera (35.3%). In these 24 sera the antigenic targets were BPI in 14, cathepsin G in 13, and MPO in 8. Sera of 11 patients had reactivity against both BPI and cathepsin G. In sera, that were negative for ANCA, antibodies to BPI (4/23), cathepsin G (3/23), and MPO (1/44) were found in a small proportion of patients. Patients with antibodies to BPI had lower skin score, whereas no patient with antibodies to MPO had renal disease. CONCLUSION: BPI and cathepsin G are the major antigenic targets of ANCA seen in patients with SSc. Patients with antibodies to BPI had lower skin scores.     

Anti-neutrophil cytoplasmic antibodies (ANCA) and inflammatory bowel diseases in Chinese

Inflammatory bowel diseases are uncommon in the Chinese, but the incidence is rising. Their differentiation from infective colitis is often not clear-cut and diagnosing inflammatory bowel diseases can be difficult in Asia. We have studied Chinese patients with ulcerative colitis (N=19) and Crohn's disease (N=12) for anti-neutrophil cytoplasmic antibodies (ANCA) by indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assays (ELISA). Patients with enteric fever (N=29) and irritable bowel syndrome (N=24) were recruited as controls. Seventy-three percent of ulcerative colitis patients exhibited either p-ANCA (31%) or c-ANCA (42%) by IIF. Twenty-five percent of Crohn's disease patients were found to be p-ANCA positive. However, these ANCA were nonreactive to anti- granule, antiproteinase 3, antimyeloperoxidase, or antilactoferrin. All positive patients had extensive colitis. Sera collected from patients suffering from enteric fever and irritable bowel syndrome were negative for ANCA by IIF and ELISA. We concluded that the detection of ANCA is helpful in diagnosing inflammatory bowel diseases. Further attempts to characterize these autoantibodies are needed.This study was partly supported by the Croucher Foundation (grant 1634-29) and Research Grant Committee (grant CUHK/34/92M).     

抗中笥粒细胞胞浆抗体对溃疡性结肠炎的诊断价值

目的 探讨抗中性粒细胞胞浆抗体（ＡＮＣＡ）对溃疡性结肠炎（ＵＣ）的诊断价值。方法 应用间接免疫荧光法（ＩＩＦ）、酶联免疫吸附法（ＥＬＩＳＡ）和免疫印法（Ｗｅｓｔｅｍ ｂｌｏｔ）分别对ＵＣ患者（５８例）、非ＵＣ患者患者（４３例）及健康献血员（５８例）进行血清ＡＮＣＡ检测。结果 ＡＮＣＡ对ＵＣ诊断的敏感性为３７．９３％,特异性为１００％。ＵＣ患者中依据病情分为轻、中、重度组,ＡＮＣＡ的阳性率分别为１７     

抗中性粒细胞胞浆抗体对溃疡性结肠炎的诊断价值

目的　探讨抗中性粒细胞胞浆抗体 (ANCA)对溃疡性结肠炎 (UC)的诊断价值。方法　应用间接免疫荧光法 (IIF)、酶联免疫吸附法 (ELISA)和免疫印迹法 (Westernblot)分别对UC患者 ( 5 8例 )、非UC患者 ( 4 3例 )及健康献血员 ( 5 8例 )进行血清ANCA检测。结果　ANCA对UC诊断的敏感性为 3 7.93 % ,特异性为 10 0 %。UC患者中依据病情分为轻、中、重度组 ,ANCA的阳性率分别为17 65 %、4 1.67%和 5 2 .94 %。ANCA阳性肠黏膜炎症III～V级者占 78 95 % ,黏膜血管炎发生率为78 95 % ,而ANCA阴性者分别为 3 7.0 4 %和 4 4.4 4%。髓过氧化物酶 (MPO)、杀菌 /通透性增强蛋白(BPI)、乳铁蛋白 (LF)、组织蛋白酶G(CG)、蛋白酶 3 (PR 3 ) 5种ANCA抗原与UC患者血清的结合率分别为 13 .79%、13 .79%、10 .3 4%、10 .3 4%和 8.62 %。采用Westernblot法对UC患者血清进行检测 ,发现显示特异蛋白条带者占 4 8.2 8% ,其中显示分子量为 4 70 0 0条带者最多 ,占 2 2 .4 1%。结论　ANCA检测可作为UC的辅助诊断手段。目前 ,UC相关ANCA的靶抗原仍未明确 ,研究发现 4 70 0 0蛋白可能是UC相关ANCA的靶抗原之一。ANCA可能参与UC的致病机制。     

Contribution of immunofluorescence to identification and characterization of antineutrophil cytoplasmic antibodies in inflammatory bowel disease

We evaluated the combined use of different fixatives for the identification of atypical perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) in patients with inflammatory bowel diseases (IBD) by indirect immunofluorescence (IIF). Sera from 59 ulcerative colitis (UC) and 37 Crohn’s disease (CD) patients, and from 64 healthy controls were studied. The IIF on ethanol-, formalin-, and methanol-fixed neutrophils was used for the detection of ANCA. Enzyme linked immunosorbant assay (ELISA) was performed to identify the antigens recognized by ANCA. ANCAs were present in 35 of 59 (59.3%) UC patients and in 10 of 37 (27.02%) CD patients. Atypical p-ANCA positivity was strongly associated with UC disease (44.1% in UC vs. 8.1% in CD; p = 0.0002). The combined application of different fixatives contributed to make easy the differentiation between typical p-ANCA and atypical p-ANCA. Atypical p-ANCA determination appears to be a useful parameter for the distinction between UC and CD.     

Anti-neutrophil cytoplasmic antibodies (ANCA) in sera from patients with inflammatory bowel disease (IBD)

Anti-neutrophil cytoplasmic antibodies producing a perinuclear fluorescence pattern on ethanol-fixed granulocytes (p-ANCA) were found in 33 of 67 patients (49%) with ulcerative colitis (UC) but also in 14 of 35 patients (40%) with Crohn's disease (CD). In the latter condition p-ANCA were equally present in subgroups with colonic, ileocolonic, or ileal involvement only. Titers of p-ANCA were higher in patients with UC compared to CD patients, in particular when comparing patients with active disease. In contrast to findings in CD, patients with active UC had higher titers of p-ANCA than patients with inactive UC. Although p-ANCA were incidentally directed to lactoferrin, both in UC and CD, and to proteinase-3 and myeloperoxidase in UC only, the antigenic nature of p-ANCA could not be identified in most of the cases. We conclude that, within the spectrum of inflammatory bowel disease, the presence of p-ANCA is not specific for UC. When titers of p-ANCA are taken into account, the presence of high-titered p-ANCA, however, suggests active UC.     

抗嗜中性粒细胞胞浆抗体与狼疮性肾炎的关系

目的探讨抗嗜中性粒细胞胞浆抗体（ANCA）与狼疮性肾炎（LN）临床相关表现和发病机制的关系。方法分别应用间接免疫荧光法和酶联免疫吸附分析的方法，检测81例LN患者血清中的ANCA，并分析ANCA与LN临床表现和其它实验室检查结果之间的关系。结果单用间接免疫荧光法检测时，ANCA在LN中的阳性率是30.9％（25／81）。对间接免疫荧光法检测为阳性的血清，用酶联免疫吸附分析法进行验证，结果仅有72.0％（18／25）仍为阳性，全部是核周型ANCA（p-ANCA），未见中央型ANCA（c-ANCA）出现。ANCA阳性组LN患者合并浆膜炎、神经系统累及、贫血、抗ds-DNA抗体阳性和低补体的频率均显著高于ANCA阴性组LN患者。结论ANCA在LN中的阳性率为30.9％，并与LN特定的临床表现相关，提示ANCA可能参与了LN的发病过程。     

Neutralization of the activity of a Fasciola hepatica cathepsin L proteinase by anti-cathepsin L antibodies

Fasciola hepatica secretes a cathepsin L proteinase that is suggested to play an in vivo role in immunoprotection since the enzyme can cleave host immunoglobulin. In the present report, rabbit anti-cathepsin L IgG was shown to bind to the cathepsin L enzyme and inhibit its ability to cleave IgG molecules. Cathepsin L can prevent the antibody-mediated attachment of eosinophils to newly excysted juveniles in in vitro assays; however, if anti-cathepsin L IgG are mixed with the cathepsin L prior to the addition of the enzyme to the assay, eosinophils attach to the newly excysted juveniles. Thus it is possible to prepare antibodies that can bind and disrupt the biological activity of the F. hepatica cathepsin L.     

pANCA and ASCA in the diagnosis of different subtypes of inflammatory bowel disease

BACKGROUND/AIMS: The measurement of perinuclear antineutrophil cytoplasmic (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) has recently been suggested as a valuable and noninvasive diagnostic approach in the differentiation of ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis (IC). The aim of the study was to determine the prevalence of pANCA and ASCA in patients with inflammatory bowel disease (IBD) subgroups of different clinical course and to assess their accuracy in differential diagnosis. METHODOLOGY: The study was performed in 109 patients: 50 patients with UC, 17 with CD, 18 with IC and 24 non-IBD controls. Antibodies status has been measured with ELISA, using commercial antibody panel by MedTek kits, confirmed by IIF technique using Euroimmun panels. RESULTS: Sensitivity and specificity of pANCA+/ ASCA- pattern for UC diagnosis was 36% and 98%; pANCA-/ASCA+ for CD: 35% and 88%, pANCA/ASCA- for IC: 72% and 63%, respectively. In addition the significant positive correlation between antibodies profiles: pANCA+/ASCA- and active disease; pANCA-/ASCA+ and number of operations, as well as the negative correlation between pANCA-/ASCA- and patient's age has been found. CONCLUSIONS: Our study lends further support to the opinions that serologic assessment identifies a large subset of different subtypes of IBD patients.     

Pancreatic Autoantibodies in Greek Patients with Inflammatory Bowel Disease

Pancreatic autoantibodies (PAbs) have been suggested as a specific but not sensitive marker for Crohn's disease (CD). The aim of this study was to assess the value of detecting PAbs in Greek patients with ulcerative colitis (UC) and CD. Sera were collected from 150 patients with IBD (73 with UC and 77 with CD), 31 cases with non-IBD intestinal inflammation, 16 cases with other autoimmune diseases, and 104 healthy controls. Determination of PAbs was performed by a standard indirect immunofluorescence technique. PAbs were detected in 18 of 73 (24.7%) samples from UC patients and in 32 of 77 (41.6%) samples from CD patients. The prevalence of positive PAbs was significantly higher in CD than in UC (P= 0.04). None of the 104 samples from healthy controls and the 31 cases with non-IBD intestinal inflammation had detectable PAbs. One patient with Sjogren's syndrome was PAbs positive. No association of PAbs with IBD activity, IBD localization, or medical treatment was found. Patients with stenotic CD had a significantly higher prevalence of PAbs positivity (60%) compared with patients with inflammatory (28.6%) and fistulizing (41.2%) disease (P= 0.02). The prevalence of PAbs in Greek CD patients was found to be similar to that in previous reports. In contrast to these studies we found also increased prevalence of PAbs in UC patients. These findings suggest that PAbs should be considered as a specific marker for IBD rather than for CD.     

Detection of anti-cord factor antibodies in intestinal tuberculosis for its differential diagnosis from Crohn's disease and ulcerative colitis

We have developed a diagnostic method for pulmonary tuberculosis by detecting antibody to cord factor using enzyme-linked immunosorbent assay (ELISA). This study was to evaluate the usefulness of our method for a diagnosis of intestinal tuberculosis, and especially its ability to differentiate this disease from other inflammatory bowel diseases. Antibodies of the immunoglobulin G class against cord factor (trehalose-6,6'-dimycolate) from 27 patients with intestinal tuberculosis, 16 patients with Crohn's disease (CD), and 27 patients with ulcerative colitis (UC) were tested by ELISA with cord factor purified fromMycobacterium tuberculosis H37Rv as the antigen. Twenty-three of the 27 patients with intestinal tuberculosis (85%) showed elevated values distinct from healthy controls. None of the patients with CD showed an elevation of antibody titers. Of the 27 patients with UC, 26 (96%) did not show any anti-cord factor antibody elevation. We conclude that this method is simple and results are reproducible. The results of our study justify undertaking the detection of anti-cord factor antibodies to diagnose intestinal tuberculosis.     

Circulating autoantibodies against purified colonic mucin in ulcerative colitis

To clarify the role of colonic mucin in the autoimmune process of ulcerative colitis, circulating antibodies against human colonic mucin were investigated. Purified colonic mucin, obtained from human colonic mucosa by gel filtration, using a Bio-Gel A-1.5-m column and CsCl equilibrium density gradient, was divided into soluble mucin (S-mucin) secreted extracellularly and membranous mucin (M-mucin) binding to cell membrane. Sodium dodecylsulfate polyacrylamide gel electrophoresis and Western blotting analysis showed that antibodies in the serum samples of some patients with ulcerative colitis recognized purified S- and M-mucin of >180-kD. By enzyme-linked immunosorbent assay (ELISA), anti-mucin antibodies were detected in 11 of 60 patients with ulcerative colitis (18%). In contrast, the antibodies were not detected in 22 patients with Crohn's disease. The titers of anti-mucin antibodies against S-mucin and M-mucin were not different in each patient. By ELISA using mucin in which the sugar chains were destroyed by neuraminidase or NaIO₄ treatment, it was demonstrated that anti-mucin antibodies recognized the epitopes of either the sugar chain or the core protein exposed through destruction of the sugar chains. We then investigated the relationship between anti-mucin antibodies and the patients' clinical features. Anti-mucin antibodies were detected in 6 of 15 patients with chronic continuous type ulcerative colitis (40%) and in 5 of 26 patients with relapsing-remitting type (19%), but there was no anti-mucin antibody-positive serum in patients who had had only one attack without any relapse. These results suggest that anti-mucin antibodies could be a disease marker for ulcerative colitis and that immunological abnormalities in colonic mucin contribute to the persistence of colonic mucosal inflammation. Received: January 21, 1999 / Accepted: July 23, 1999     

Immunoglobulin G subclass distribution of human anticolon antibodies in ulcerative colitis

Abstract 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.     

Perinuclear anti-neutrophil cytoplasmic antibodies （p-anca） in chronic ulcerative colitis： Experience in a Mexican institution

AIM: To assess the prevalence and clinical value of p-ANCA in a sample of Mexican ulcerative colitis (UC) patients. METHODS: In a prospective, IRB-approved protocol, p-ANCA was determined in 80 patients with UC (mean age, 32±12.9 years). The severity and extension of disease were determined by clinical methods, searching a statistical association with p-ANCA status. RESULTS: p-ANCA were detected in 41 (51%) patients. Severity of disease was the only clinical variable statistically associated with their presence (P < 0.0001; OR = 9; CI 95% = 3.2-24.7). CONCLUSION: The prevalence of p-ANCA was similar to that reported in other countries. Their presence was associated to UC severity, but offered no more information than the obtained by clinical methods.