Anti‐Saccharomyces cerevisiae mannan antibodies in inflammatory bowel disease: comparison of different assays and correlation with clinical features

Abstract

Summary Background : Anti‐Saccharomyces cerevisiae mannan antibodies have been proposed as a new serological marker associated with Crohn's disease. However, their clinical value is still unclear; furthermore, a standardization of anti‐S. cerevisiae mannan measurements is lacking. Aim : In this study, we aimed to assess the correlation between anti‐S. cerevisiae mannan detection and specific clinical features in Crohn's disease and ulcerative colitis. Moreover, we tested the concordance of four different anti‐S. cerevisiae mannan assays. Materials and methods : Serum samples from 196 patients with Crohn's disease, 197 patients with ulcerative colitis and 100 unrelated healthy controls were tested for anti‐S. cerevisiae mannan with a standard enzyme‐linked immunosorbent assay method (Lille) by one of the authors (VP). Subsequently, 60 randomly selected serum samples (27 Crohn's disease, 28 ulcerative colitis and five healthy controls) were tested for anti‐S. cerevisiae mannan with three different commercial kits. Results : With the Lille assay, anti‐S. cerevisiae mannan were detected in 100 of 196 patients with Crohn's disease (51%; P < 0.0001 vs. controls), 32 of 197 patients with ulcerative colitis (16%; P < 0.02 vs. controls), and six of 100 controls (6%). No correlation between presence of anti‐S. cerevisiae mannan and specific clinical features was found in both ulcerative colitis and Crohn's disease patients. The percentages of anti‐S. cerevisiae mannan detected with four different assays ranged from 28 (Bouty) up to 43% (Inova), but these differences did not reach statistical significance. The concordance rate of anti‐S. cerevisiae mannan detection in the four assays was very low (11 concordant results of 60 samples, 18.3%) (k = 0.15). No improvement of the concordance rate wasobtained by modifying the suggested cut‐off values (k = 0.20). Conclusion : In this study, we confirm that anti‐S. cerevisiae mannan are significantly more frequent in Crohn's disease patients compared with ulcerative colitis patients (P < 0.0001) and controls. However, no correlation with clinical features was found in both ulcerative colitis and Crohn's disease. The low prevalence of anti‐S. cerevisiae mannan, at least in our population, and the low concordance rate between different assays, makes the clinical role of this marker questionable.

HLA-DRB1 Alleles May Influence Disease Phenotype in Patients With Inflammatory Bowel Disease: A Critical Reappraisal With Review of the Literature

“…41 Control serum (100 µl; high positive, low positive, and negative) and 1:100 diluted serum samples from patients were added to separated polystyrene microwells coated with partially purified and disrupted Saccharomyces cerevisiae antigen. After incubation for 30 minutes at 37°C, unbound samples were washed away, and 100 µl of horseradish peroxidase (HRP) immunoglobulin G or A (IgG or IgA) conjugate (goat anti-human) was added.…”

Pesquisa de anticorpos contra estruturas citoplasmáticas do neutrófilo (ANCA) e contra o Saccharomyces cerevisiae (ASCA) na doença inflamatória intestinal

“…Vários "kits" comerciais estão disponíveis no mercado tornando o acesso ao exame relativamente fácil. Entretanto, pode ser percebida variações dos resultados entre os "kits" empregados de diferentes laboratórios, podendo refletir variações dependentes da metodologia empregada (51).…”

“…Isso foi demonstrado em alguns trabalhos que tiveram como objetivo avaliar a variação existente entre as metodologias empregadas na detecção do P-ANCA e ASCA na DII (5,51,62).…”

“…Alguns estudos também evidenciaram associação com comportamento mais agressivo, ou seja, com as formas penetrantes e fibroestenosantes (22,43,44,75). No entanto, muitos outros trabalhos não evidenciaram tal associação, bem como com outras características clínicas -como história de cirurgias ou tratamento mais agressivo, clínico ou cirúrgico (51,77).…”

“…Podemos perceber que a maioria dos pacientes com DC estudados, apresentava-se em fase de remissão ou com doença leve, o que pode ter prejudicado esta avaliação. Entretanto, a maioria dos trabalhos não mostrou associação entre a atividade da doença com a presença do anticorpo (49,51).…”