Neutrophil autoantibodies in inflammatory bowel disease: are they important?

Anti-pancreatic antibody in Turkish patients with inflammatory bowel disease and first-degree relatives

AIM: To identify the role of anti-pancreatic antibody (PAB) in the diagnosis of inflammatory bowel diseases (IBD) among Turkish patients, and its frequency in first-degree relatives.

METHODS: PAB and anti-Saccharomyces cerevisiae (ASCA) were examined in serum samples of 214 subjects including patients with Crohn’s disease (CD, n = 64), ulcerative colitis (UC, n = 63), first-degree relatives of patients with CD (n = 25), first-degree relatives of patients with UC (n = 28),and a control group with gastrointestinal symptoms other than (IBD) (n = 34) by indirect immunofluorescence Positivity of PAB and ASCA was compared in terms of Vienna classification, disease activity and medications used.

RESULTS: In terms of PAB positivity, no difference was found between patients with CD (14.1%) and UC (7.9%) however, significant difference was observed between patients with CD and subjects in the control group (P < 0.05). No difference was found between patients with CD and their relatives in terms of ASCA positivity, whereas a significant difference was found between other groups (P < 0.001). Compared to ASCA, the sensitivity of the PAB was 19% (7/37), its specificity was 93% (25/27), positive predictive value was 77% (7/9) and negative predictive value was 45% (25/55). ASCA was found with significantly higher prevalence in patients with CD activity index > 150 (P < 0.05).

CONCLUSION: PAB is valuable in the diagnosis of IBD rather than CD, but cannot be used alone for diagnostic purposes. PAB is not superior to ASCA in CD diagnosis and in detecting CD among relatives of patients with CD.

Diagnostic precision of anti-Saccharomyces cerevisiae antibodies and perinuclear antineutrophil cytoplasmic antibodies in inflammatory bowel disease

AIMS

The aim of this study was to assess the diagnostic precision of antiSaccharomyces cerevisiae (ASCA) and perinuclear antineutrophil cytoplasmic antibodies (pANCA) in inflammatory bowel disease (IBD) and evaluate their discriminative ability between ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Meta-analysis of studies reporting on ASCA and pANCA in IBD was performed. Sensitivity, specificity, and likelihood ratios (LR+, LR-) were calculated for different test combinations for CD, UC, and for IBD compared with controls. Meta-regression was used to analyze the effect of age, DNAse, colonic CD, and assay type.

RESULTS

Sixty studies comprising 3,841 UC and 4,019 CD patients were included. The ASCA+ with pANCA- test offered the best sensitivity for CD (54.6%) with 92.8% specificity and an area under the ROC (receiver operating characteristic) curve (AUC) of 0.85 (LR+ = 6.5, LR- = 0.5). Sensitivity and specificity of pANCA+ tests for UC were 55.3% and 88.5%, respectively (AUC of 0.82; LR+ = 4.5, LR- = 0.5). Sensitivity and specificity were improved to 70.3% and 93.4% in a pediatric subgroup when combined with an ASCA- test. Meta-regression analysis showed decreased diagnostic precision of ASCA for isolated colonic CD (RDOR = 0.3).

CONCLUSIONS

ASCA and pANCA testing are specific but not sensitive for CD and UC. It may be particularly useful for differentiating between CD and UC in the pediatric population.

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.

A prospective comparative study of ASCA and pANCA in Chinese and Caucasian IBD patients

BACKGROUND

Inflammatory bowel disease manifests throughout all ethnic groups. Antisaccharomyces cerevisiae (ASCA) and antineutrophil cytoplasmic antibodies (pANCA) can aid in the differentiation between Crohn's disease (CD) and ulcerative colitis (UC), but their sensitivity may vary between races.

OBJECTIVES

This study compared the sensitivity, specificity, and positive and negative predictive values (PPV, NPV) of pANCA and ASCA between Chinese and Caucasian IBD populations and identified disease subtype associations.

RESULTS

Three hundred patients were prospectively recruited from Caucasian and Chinese populations (CD, n = 50, UC, n = 50, controls, n = 50 each). pANCA detection was greater in Caucasian than Chinese UC patients (p= 0.046). ASCA IgG detection was similar, but IgA was lower in Chinese CD patients (p < 0.001). Differentiation between UC and CD (+ve pANCA/-ve ASCA) demonstrated a PPV of 92% in isolated colonic disease. Logistic regression in CD identified positive pANCA had a lower association with ileal (OR = 6.8, p= 0.0067) and complicated disease (OR = 5.5, p= 0.015). Caucasian CD patients with positive ASCA IgA/IgG had a greater association with ileal (OR = 6.7, p= 0.022) or complicated disease (OR = 9.4, p= 0.0073) and in Chinese CD patients positive ASCA IgA/IgG was associated with isolated ileal disease (OR = 16.8, p= 0.032). Linear regression demonstrated that higher ASCA titers predicted complicated CD and isolated ileal disease.

CONCLUSIONS

This study identified that pANCA is more sensitive in Caucasian than Chinese UC and that ASCA IgA has a low yield in Chinese CD. pANCA and ASCA are useful for differentiating between UC and CD in both populations, and ASCA IgG and IgA titers have potential use in determining the risk of developing complicated CD.

Antineutrophil cytoplasmic antibodies in inflammatory bowel disease: clinical role and review of the literature

PURPOSE

Perinuclear antineutrophil cytoplasmic antibodies have been found consistently in patients with ulcerative colitis; however, their pathogenetic and clinical role is still uncertain. In this study we tested the prevalence of perinuclear antineutrophil cytoplasmic antibodies in a large population of patients with ulcerative colitis and Crohn's disease, with particular attention to the possible correlation with clinical features.

METHODS

Perinuclear antineutrophil cytoplasmic antibody reactivity was investigated with indirect immunofluorescence in 279 patients with ulcerative colitis, 110 patients with Crohn's disease, and 252 unrelated healthy subjects.

RESULTS

Perinuclear antineutrophil cytoplasmic antibodies were found in 84 of 279 patients with ulcerative colitis (30 percent), 10 of 110 patients with Crohn's disease (9 percent), and 2 of 252 healthy subjects (<1 percent; P < 0.001), respectively. Perinuclear antineutrophil cytoplasmic antibodies were significantly more frequent in patients with ulcerative colitis with higher relapse rate (43 vs. 27 percent; P < 0.002), and patients with Crohn's disease with colitis (27 vs. 2.5 percent; P < 0.0003). Perinuclear antineutrophil cytoplasmic antibodies were also significantly less frequent in patients with ulcerative colitis in remission (18 vs. 34 percent; P < 0.0025).

CONCLUSIONS

In this study we confirm the relative specificity of perinuclear antineutrophil cytoplasmic antibodies, either for ulcerative colitis or for Crohn's disease involving the colon. Perinuclear antineutrophil cytoplasmic antibodies were more frequently found in patients with ulcerative colitis with a more aggressive clinical behavior; however, their presence had a limited value in identifying homogeneous subgroups of patients in our population.

Are anti-neutrophil cytoplasmic antibodies (ANCA) clinically useful in inflammatory bowel disease (IBD)?

Since the first detection of ANCA in IBD, numerous studies have dealt with their prevalence, antigenic specificities, clinical significance, pathophysiological role, and their induction. This review summarizes the information obtained from those studies and shows that ANCA are not directly useful as diagnostic and prognostic factors in IBD. ANCA were detected in 50-85% of patients with ulcerative colitis (UC) and 10-20% of patients with Crohn's disease (CD). Multiple target antigens are recognized by these autoantibodies, including both cytoplasmic and nuclear proteins. A pathophysiological role for ANCA in IBD is far from clear. On the one hand, it is suggested that ANCA are genetic markers of susceptibility for IBD, and on the other hand, the induction of ANCA in those diseases may just be an epiphenomenon of chronic inflammation. We discuss recent evidence that ANCA may be induced by a break-through of tolerance towards bacterial antigens.

Antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis: defined specificities may be associated with distinct clinical features

PURPOSE

The clinical significance of antineutrophil cytoplasmic autoantibodies (ANCA) in primary sclerosing cholangitis has not been established. We investigated whether analysis of the antigenic specificities of ANCA is useful for delineating clinical subsets of the disease.

METHODS

Sixty-nine patients with primary sclerosing cholangitis were studied. The presence of ANCA was analyzed by indirect immunofluorescence. Antibodies directed against specific antigens--proteinase 3, myeloperoxidase, elastase, bactericidal/permeability-increasing protein, cathepsin G, and lactoferrin--were identified by enzyme-linked immunosorbent assay.

RESULTS

ANCA were detected by indirect immunofluorescence in 46 (67%) patients. In antigen-specific enzyme-linked immunosorbent assays, 37 (55%) of the 69 patients had antibodies to one or more antigens: 32 (46%) had antibodies to bactericidal/permeability-increasing protein, 16 (23%) had antibodies to cathepsin G, and 15 (22%) had antibodies to lactoferrin. Only 3 patients had antibodies to proteinase 3. Antibodies to myeloperoxidase or elastase were not detected. Twenty (29%) patients had antibodies to different antigens simultaneously. ANCA as detected by indirect immunofluorescence were not significantly associated with the presence of cirrhosis nor with the coexistence of inflammatory bowel disease. However, antibodies to bactericidal/permeability-increasing protein and cathepsin G were both associated with the presence of cirrhosis, and antibodies to lactoferrin were more frequently detected in patients with primary sclerosing cholangitis in conjunction with ulcerative colitis than in those without inflammatory bowel disease.

CONCLUSION

Defined specificities of ANCA in primary sclerosing cholangitis may be related to particular clinical features of the disease.

Catalase and alpha-enolase: two novel granulocyte autoantigens in inflammatory bowel disease (IBD)

In IBD, the target antigens of anti-neutrophil cytoplasmic autoantibodies (ANCA) have not been fully identified, which limits the analysis of the diagnostic significance as well as of the possible pathophysiological role of these antibodies. In this study, we identify the target antigens of ANCA in large groups of patients with ulcerative colitis (UC) and Crohn's disease (CD). Apart from antibodies against lactoferrin and bactericidal/permeability-increasing protein (BPI), which have been reported before, antibodies against two novel granulocyte antigens were identified: antibodies against a 57/56-kD doublet were found in 38% of samples from UC patients and in 26% of samples from CD patients, whereas antibodies against a 47-kD protein were found in 10% of samples from UC patients and in 18% of samples from CD patients. Partial purification and amino acid sequence analysis identified the 57-kD protein as catalase and the 47-kD protein as alpha-enolase. This study is the first to report catalase and alpha-enolase as granulocyte antigens for autoantibodies in IBD.

Antineutrophil cytoplasmic antibodies in children with inflammatory bowel disease: prevalence and diagnostic value

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCA), particularly perinuclear ANCA (p-ANCA), have been found more frequently in sera from patients with ulcerative colitis (UC) than in sera from Crohn's disease (CD) or unclassified enterocolitis (UE) patients. This 2-center study examined sera from 102 pediatric patients with inflammatory bowel disease (IBD) to evaluate their diagnostic value and assess their relationship with disease features, distribution, activity and treatment.

METHODS

The serum ANCA of 102 children with IBD were measured: 33 UC, 64 CD and 5 UE with various disease locations and degrees of activity. The mean age at the onset of symptoms was 10.7 years (1 to 16.3 years). Sera from 26 unaffected first degree relatives and 20 children without IBD were also investigated. ANCA were detected using indirect immunofluorescence of ethanol-fixed granulocytes.

RESULTS

There were ANCA in the sera of 24/33 children with UC (73%), 9/64 with CD (14%) and 4/5 with UE (80%). p-ANCA were more frequent than cytoplasmic-ANCA in positive sera: UC = 67%, CD = 57% and UE = 75%. The presence of ANCA was 73% sensitive and 81% specific for a diagnosis of UC, compared to other IBD (p < 0.001). Three children with proved sclerosing cholangitis associated with UC were all positive. There was no link between ANCA-positive sera and disease activity, or other endoscopic or clinical criteria. ANCA were detected in 4/26 first degree relatives (15%) and in 1/20 control subjects (5%).

CONCLUSIONS

Because of their sensitivity and specificity, ANCA may be helpful in the clinical assessment of patients with IBD, and especially those with UC. However, there is no link between the pressure of p-ANCA and the site of UC or its activity, so that it cannot be used to monitor medical treatment or surgical indications.

Antineutrophil cytoplasmic antibodies in sera from colectomised ulcerative colitis patients and its relation to the presence of pouchitis

BACKGROUND

Few studies have evaluated the influence of colectomy on antineutrophil cytoplasmic antibody (ANCA) positivity in ulcerative colitis (UC). In small series of patients it has been suggested that ANCA positivity in UC might be predictive for development of pouchitis after colectomy.

AIMS

To assess the prevalence of ANCA in UC patients treated by colectomy and a Brooke's ileostomy (UC-BI) or ileal pouch anal anastomosis (UC-IPAA), and the relation between the presence of ANCA, the type of surgery, and the presence of pouchitis.

SUBJECTS

63 UC patients treated by colectomy (32 with UC-BI and 31 with UC-IPAA), 54 UC, and 24 controls.

METHODS

Samples were obtained at least two years after colectomy. ANCA were detected by indirect immunofluorescent assay.

RESULTS

There were no differences between patients with (36.3%) or without pouchitis (35.0%) and between patients with UC (55%), UC-BI (40.6%), and UC-IPAA (35.4%). However, ANCA prevalence significantly decreases in the whole group of operated patients (38.0%) compared with non-operated UC (p = 0.044).

CONCLUSIONS

The prevalence of ANCA in operated patients was significantly lower than in non-operated UC, suggesting that it might be related either to the presence of inflamed or diseased tissue. ANCA persistence is not related to the surgical procedure and it should not be used as a marker for predicting the development of pouchitis.

Differential expression of substance P receptors in patients with Crohn's disease and ulcerative colitis

BACKGROUND & AIMS

Although clinical and pathological differences exist between Crohn's disease (CD) and ulcerative colitis (UC), distinguishing features are often absent, making diagnosis and treatment problematic. This study evaluated the differences in the expression of substance P (SP) receptors in patients with CD or UC.

METHODS

Tissue samples from patients with inflammatory bowel disease or control patients were obtained at surgery, processed for 125I-SP binding, and analyzed by quantitative autoradiography.

RESULTS

Patients with CD showed a massive increase in SP receptors in lymphoid aggregates, small blood vessels, and enteric neurons of the small and large bowel relative to controls. Six of 16 CD specimens had no pathological evidence of CD yet continued to express high concentrations of SP receptors. Pathologically positive patients with UC showed high concentrations of SP receptors on colonic lymphoid aggregates and small blood vessels but not enteric neurons. No increased SP binding was evident in clinically and pathologically quiescent UC colons and normal UC ileostomy samples.

CONCLUSIONS

The increased expression of SP receptors on the enteric neurons of patients with CD distinguishes CD from UC. The persistent increased SP binding in pathologically normal CD tissue may indicate a subclinical disease state. SP receptor expression may have important diagnostic, etiologic, and therapeutic usefulness in inflammatory bowel disease.

Intercellular adhesion molecule 1 gene associations with immunologic subsets of inflammatory bowel disease

BACKGROUND & AIMS

Inflammatory bowel disease is characterized by a failure to down-regulate the usual self-limited gut inflammatory response, suggesting that one or more of the predisposing genes could be those that determine the level of the immune response along the inflammatory pathway. The aim of this study was to examine potential associations of intercellular adhesion molecule 1 (ICAM-1) gene polymorphisms with inflammatory bowel disease or subsets of inflammatory bowel disease.

METHODS

One hundred eighteen patients with ulcerative colitis (UC) and 130 patients with Crohn's disease (CD) as well as 77 ethnically matched controls were tested for antineutrophil cytoplasmic antibodies (ANCAs) and genotyped by polymerase chain reaction and allele-specific oligonucleotide techniques for ICAM-1 polymorphisms at codon 241 (exon 4) and codon 469 (exon 6).

RESULTS

There was no significant difference between all patients with UC, patients with CD, and controls in either polymorphism. However, when stratified by ANCA status, ANCA-negative UC showed a significantly increased frequency of allele R241 compared with ANCA-positive UC (16.0% vs. 6.6%; P = 0.047, Fisher's Exact Test). In contrast, it was ANCA-positive CD that had an increased allele frequency compared with ANCA-negative CD (19.6% vs. 8.4%; P = 0.027, Fisher's Exact Test).

CONCLUSIONS

Because the codon 241 polymorphism is in a functionally important domain III of ICAM-1, we may have identified an actual responsible genetic variation for genetically heterogeneous subsets of both UC and CD.

Current concepts of the pathogenesis of inflammatory bowel disease

Although the cause of inflammatory bowel disease is not known, the pathogenesis involves an immune-mediated tissue damage that is the result of an interaction among genetic predisposing factors, exogenous triggers and endogenous modifying influences. Multiple genes are involved and operate at the level of the immune response and at the target organ. Exogenous triggers include the enteric microflora which might stimulate the mucosal immune system in genetically predisposed individuals. Endogenous modifying factors such as the psychoneuroendocrine system have regulatory effects on the immune system and the inflammatory response, and may influence the course of the disease. While autoimmune phenomena do occur, particularly in ulcerative colitis, there is no evidence that they are directly responsible for the tissue damage. It appears more likely, particularly in Crohn's disease, that tissue injury may occur as an indirect or "bystander" effect of mucosal T-cell hyperactivation, perhaps in response to a normal enteric microbial antigen. Most of the immunologic and histologic features of Crohn's disease can be explained by the effects of T-cell derived and other cytokines on the epithelium, the local immune system, the microvasculature, and the recruitment of auxiliary effector cells such as neutrophils.