Serological markers (anti-Saccharomyces cerevisiae mannan antibodies and antineutrophil cytoplasmic antibodies) in inflammatory bowel disease: diagnostic utility and phenotypic correlation

Assessment of clinical activity and severity using serum ANCA and ASCA antibodies in patients with ulcerative colitis

Background

Ulcerative colitis (UC) is a chronic, non-specific inflammatory bowel disease (IBD) with unknown etiology. The lack of specific clinical manifestations, standard diagnostic criteria, objective and accurate indicators to the severity of the disease and the efficacy of the treatment, often results in difficulties in diagnosis and timely treatment of UC. Therefore, there is a need to develop a clinically suitable serum biomarker assay with high specificity and sensitivity.

Objective and methods

To explore the significance of anti-neutrophil cytoplasmic antibodies (ANCA) and anti-saccharomyces cerevisiae antibodies (ASCA) in the diagnosis, differential diagnosis and treatment assessment in patients with ulcerative colitis (UC). Serum levels of ANCA-IgG, ASCA-IgA and ASCA-IgG were measured by an enzyme-linked immunosorbent assay (ELISA) in 105 UC patients, 52 non-UC patients and 100 healthy controls.

Results

(1) Both the ANCA-IgG level and its positive rate in UC patients were significantly higher than those in non-UC controls and healthy controls (p < 0.01). However, the levels of ASCA-IgA, ASCA-IgG and the positive rates in UC patients had no statistical differences when compared with those in non-UC controls or healthy controls (p > 0.05). (2) The sensitivity of ANCA⁺ and ANCA⁺/ASCA^- in detecting UC patients was 61.90% and 55.24%, respectively, whereas the specificity was 91.45% and 94.08%, respectively. The sensitivity of ASCA⁺ and ASCA⁺/ANCA^- in non-UC disease controls was 5.33% and 3.85%, respectively, and specificity was 83.9% and 88.78%, respectively. (3) When UC patients were grouped into mild, moderate or severe subtypes, the ANCA-IgG levels were correlated with the severity of UC, and the differences of the ANCA-IgG levels were statistically different among the three subtypes (p < 0.05). There was no correlation between the levels of ANCA-IgG and the disease locations of UC.

Conclusions

(1) Serum levels of ANCA may be useful in the diagnosis of UC. (2) Dynamic quantitation of ANCA-IgG levels may be helpful in determining the severity of UC and therefore, may guide treatment of UC.

Development of an indirect immunofluorescence based assay for diagnosis of ulcerative colitis in Indian population

The prevalence of Ulcerative Colitis (UC), once thought to be negligible, has increases exponentially in the Indian population. The development of novel, cost effective and time efficient Indirect Immunofluorescence (IIF) based assay for detection of anti-neutrophil cytoplasmic antibodies (ANCA) and diagnosis of UC in the Indian population is discussed. A novel IIF based assay was developed using intact nuclei from human neutrophils to detect atypical p-ANCA in patients suffering from UC. Sera from 45 patients diagnosed with UC, 45 healthy controls and one related disease control were tested using a novel UC-ANCA assay and validated by commercially available ANCA IIF assay. Prevalence of ANCA amongst UC patients in the Indian population was determined. Atypical p-ANCA was detected in 86.6% of the patients using the UC-ANCA assay as compared to 71.1% using the commercial ANCA assay. The validation of UC-ANCA assay with a commercially available ANCA IIF assay resulted in higher sensitivity. The UC-ANCA assay proved to be not only enhanced in terms of performance but also comparatively economical and rapid. The novel UC-ANCA assay may prove to be very useful in identification and differentiation of UC patients from typical ANCA positive subjects suffering from other autoimmune diseases at one tenth the cost of clinically available ANCA IIF tests which will immensely benefit the cost constrained diagnostic field of developing countries.

Serum antibodies associated with complex inflammatory bowel disease

BACKGROUND

Antibodies to microbial antigens have been associated with specific diagnoses and phenotypes of inflammatory bowel disease. We evaluated the prevalence of pANCA, IgA and IgG anti-Saccharomyces cerevisiae antibodies, anti-OmpC, and anti-flagellin in a large well-defined population of patients with Crohn's disease (CD) and ulcerative colitis (UC) and analyzed for various clinical outcomes.

METHODS

Samples were collected from 391 patients with CD, 207 patients with UC, and 62 healthy controls. Patients were phenotyped using the Montreal classification. Blinded serological analyses were performed for pANCA, IgA and IgG anti-Saccharomyces cerevisiae antibodies, anti-OmpC, and anti-flagellin.

RESULTS

In CD, increasing quantitative levels for antibodies were associated with a younger age of diagnosis, longer disease duration, increased surgeries, ileocolonic and perianal disease, and internal perforating behavior. In UC, they were associated with colectomy. An increasing number of seropositive antibodies in CD was associated with a younger age at diagnosis, increased disease duration, ileocolonic and perianal disease, internal penetrating and stricturing behavior, and increased surgeries. Multivariate analysis confirmed the association of antimicrobial antibodies with features of complicated CD and UC.

CONCLUSIONS

Increased serological markers are associated with a more aggressive CD phenotype and an increased need for colectomy in UC. This raises the possibility for use of these markers in patients at risk of complex disease.

Serological markers for inflammatory bowel disease in AIDS patients with evidence of microbial translocation

BACKGROUND

Breakdown of the gut mucosal barrier during chronic HIV infection allows translocation of bacterial products such as lipopolysaccharides (LPS) from the gut into the circulation. Microbial translocation also occurs in inflammatory bowel disease (IBD). IBD serological markers are useful in the diagnosis of IBD and to differentiate between Crohn's disease (CD) and ulcerative colitis (UC). Here, we evaluate detection of IBD serological markers in HIV-infected patients with advanced disease and their relationship to HIV disease markers.

METHODS

IBD serological markers (ASCA, pANCA, anti-OmpC, and anti-CBir1) were measured by ELISA in plasma from AIDS patients (n = 26) with low CD4 counts (<300 cells/µl) and high plasma LPS levels, and results correlated with clinical data. For meta-analysis, relevant data were abstracted from 20 articles.

RESULTS

IBD serological markers were detected in approximately 65% of AIDS patients with evidence of microbial translocation. An antibody pattern consistent with IBD was detected in 46%; of these, 75% had a CD-like pattern. Meta-analysis of data from 20 published studies on IBD serological markers in CD, UC, and non-IBD control subjects indicated that IBD serological markers are detected more frequently in AIDS patients than in non-IBD disease controls and healthy controls, but less frequently than in CD patients. There was no association between IBD serological markers and HIV disease markers (plasma viral load and CD4 counts) in the study cohort.

CONCLUSIONS

IBD serological markers may provide a non-invasive approach to monitor HIV-related inflammatory gut disease. Further studies to investigate their clinical significance in HIV-infected individuals are warranted.

Diagnostic role and clinical association of ASCA and ANCA in Brazilian patients with inflammatory bowel disease

BACKGROUND

Anti-Saccharomyces cerevisae antibody (ASCA) and perinuclear anti-neutrophil cytoplasmatic antibody (pANCA) remain the most well-established markers in inflammatory bowel disease (IBD), and both may be associated with disease phenotype.

AIM

To determine the utility of ASCA and pANCA as markers in a Brazilian cohort of IBD patients.

MATERIALS AND METHODS

A total of 90 patients with ulcerative colitis (UC), 77 patients with Crohn's disease (CD), and 57 healthy individuals were included in the study. ASCA was determined by enzyme-linked immunosorbent assay (ELISA) and pANCA by immunofluorescence assay.

RESULTS

In support of diagnosis of UC, the sensitivity and specificity of pANCA were 51% and 100%, respectively. ASCA (IgA or IgG isotypes) presented sensitivity of 62% and specificity of 93% for CD. The combination of ASCA negativity and pANCA positivity (ASCA-/pANCA+) displayed sensitivity of 43% and specificity of 100% for diagnosis to UC. In CD patients, ASCA+/pANCA- presented sensitivity and specificity of 57% and 93%, respectively. Additionally, ASCA positivity correlated with early age at disease onset and ileal location in CD patients. In UC patients, pANCA positivity was correlated with pancolitis or left colitis.

CONCLUSIONS

The results evidenced that low sensitivity of ASCA and pANCA markers limits their use in IBD screening in the general population; however, their specificity may contribute to differentiation between CD and UC in IBD patients. Our study lends further support to the suggestion that serologic assessment identifies different subtypes of IBD.