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 multicent

AIM： Anti-Saccharomyces anti-nuclear associated cerevisiae antibodies （ASCA）, 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.

Partial overlap of anti-mycobacterial,and anti-Saccharomyces cerevisiae mannan antibodies in Crohn's disease

AIM： To test whether humoral immune reaction against mycobacteria may play a role in anti- Saccharomyces cerevisiae antibodies （ASCA） generation in Crohn＇s disease （CD） and/or whether it correlates with clinical subtypes. METHODS： The dominant ASCA epitope was detected by Galanthus nivalis lectin （GNL）-binding assay. ASCA and IgG against mycobacterial lysates （M avium, M smegmatis, M chelonae, M bovis BCG M avium ssp. paratuberculosis （MAP）] or purified lipoarabinomannans （LAM） were detected by ELISA. ASCA and anti-mycobacterial antibodies were affinity purified to assess cross-reactivities. Anti-mycobacterial IgG were induced by BCG-infection of mice. RESULTS： GNL bound to different extents to mycobacterial lysates, abundantly to purified mannosecapped （Man） LAM from M tuberculosis, but not to uncapped LAM from M srnegrnatis. Fifteen to 45% of CD patients but only 0%-6% of controls were seropositive against different mycobacterial antigens. Anti-mycobacterial IgG correlated with ASCA （r = 0.37-0.64; P = 0.003-P 〈 0.001）. ASCA-positivity and deficiency for mannan-binding lectin synergistically associated with anti-mycobacterial IgG. In some patients, anti-mycobacterial antibodies represent crossreactive ASCA. Vice-versa, the predominant fraction of ASCA did not cross-react with mycobacteria. Finally, fistulizing disease associated with antibodies against M avium, M smegmatis and MAP （P = 0.024, 0.004 and 0.045, respectively）. CONCLUSION： Similar to ASCA, seroreactivity against mycobacteria may define CD patients with complicated disease and a predisposition for immune responses against ubiquitous antigens. While in some patients anti-mycobacterial antibodies strongly cross-react with yeast mannan; these cross-reactive antibodies only represent a minor fraction of total ASCA. Thus, mycobacterial infection unlikely plays a role in ASCA induction.

Anti-Saccharomyces cerevisiae antibody titers are stable over time in Crohn's patients and are not inducible in murine models of colitis

AIM： To investigate ASCA production over time in CD and murine colitis in order to further our understanding of their etiology. MATERIALS AND METHODS： Sixty-six CD patients were compared to ulcerative colitis （UC） and irritable bowel syndrome patients with respect to ASCA production as measured by ELISA. ASCA IgG or IgA positivity as well as change in titers over a period of up to 3 years （△tgG/A） was correlated with clinical parameters such as CD activity index （CDM） and C-reactive protein levels （CRP）. Moreover, two murine models of colitis （DSS and IL-10 knock out） were compared to control animals with respect to ASCA titers after oral yeast exposure. RESULTS： ASCA IgG and IgA titers are stable over time in CD and non-CD patients. Fistular disease was associated with a higher rate of ASCA IgA positivity （P = 0.014）. Ileal disease was found to have a significant influence on the △tgG of ASCA （P = 0.032）. There was no correlation found between ASCA positivity or △tgG/A and clinical parameters of CD： CDAI and CRP. In mice, neither healthy animals nor animals with DSS-induced or spontaneous colitis exhibited a marked increase in ASCA titers after high-dose yeast exposure. On the other hand, mice immunized intraperitoneally with mannan plus adjuvant showed a marked and significant increase in ASCA titers compared to adjuvant-only immunized controls （P = 0.014）. CONCLUSION： The propensity to produce ASCA in a subgroup of CD patients is largely genetically predetermined as evidenced by their stability and lack of correlation with clinical disease activity parameters. Furthermore, in animal models of colitis, mere oral exposure of mice to yeast does not lead to the induction of marked ASCA titers irrespective of concomitant colonic inflammation. Hence, environment may play only a minor role in inducing ASCA.

Anti-microbial antibodies in celiac disease:Trick or treat?

AIM： To determine the prevalence of a new set ot anti-glycan and anti-outer membrane protein （anti- OMP） antibodies in a Hungarian cohort of adult Celiac disease （CD） patients. METHODS： 190 consecutive CD patients [M/F： 71/119, age：39.9 （SD：14.1） years], 100 healthy, and 48 gastrointestinal controls were tested for glycan anti-Saccharomyces cerevisiae （gASCA）, anti-laminaribioside （ALCA）, anti-chitobioside, anti-mannobioside, anti-OMP antibodies and major NOD2/CARD15 mutations. Thirty out of 82 CD patients enrolled at the time of diagnosis were re-evaluated for the same antibodies after longstanding gluten-free diet （GFD）. RESULTS： 65.9% of the CD patients were positive for at least one of the tested antibodies at the time of the diagnosis. Except anti-OMP and ALCA, antimicrobial antibodies were exclusively seen in untreated CD; however, the overall sensitivity was low. Any glycan positivity （LR＋： 3.13; 95% CI： 2.08-4.73） was associated with an increased likelihood ratio for diagnosing CD. Significant correlation was found between the levels of anti-glycan and anti-endomysial or anti-transglutaminase antibodies. Anti-glycan positivity was lost after longstanding GFD. Anti-glycan antibody titers were associated with symptoms at presentation, but not the presence of NOD2/CARD15 mutations. Patients with severe malabsorption more frequently had multiple antibodies at diagnosis （P = 0.019）. CONCLUSION： The presence of anti-glycan antibodies in CD seems to be secondary to the impaired small bowel mucosa which can lead to increased antigen presentation. Furthermore, anti-glycan positivity may be considered an additional marker of CD and dietary adherence.

Inflammatory bowel disease serology in Asia and the West

AIM:To study serological antibodies in Caucasians and Asians,in health and inflammatory bowel disease(IBD),in Australia and Hong Kong(HK).METHODS:Anti-glycan antibodies[anti-chitobioside(ACCA),anti-laminaribioside(ALCA)],and anti-mannobioside(AMCA),anti-Saccharomyces cervisiae(gASCA);and atypical perinuclear anti-neutrophil cytoplasmic antibody(pANCA)were tested in IBD patients,their unaffected relatives,and healthy controls in Australia and HK(China).Antibody status(positive or negative)and titre was compared between subjects of different geography,ethnicity and disease state.RESULTS:Ninety subjects were evaluated:21 Crohn’s disease(CD),32 ulcerative colitis(UC),29 healthy controls,and 8 IBD patient relatives.Forty eight subjects were Australian(29 Caucasian and 19 ethnic Han Chinese)and 42 were from HK(all Han Chinese).Caucasian CD patients had a significantly higher antibody prevalence of gASCA(67%vs 3%,P<0.001),ALCA(44%vs 6%,P=0.005),and AMCA(67%vs 15%,P=0.002),whereas HK CD patients had a higher prevalence of only AMCA(58%vs 25%,P=0.035),when compared with UC and healthy subjects in both countries.Caucasian CD had significantly higher gASCA prevalence(67%vs 0%,P<0.001)and titre(median59 vs 9,P=0.002)than HK CD patients.Prevalence and titres of ALCA,ACCA and AMCA did not differ between CD in the two countries.Presence of at least one antibody was higher in Caucasian than HK CD patients(100%vs 58%,P=0.045).pANCA did not differ between countries or ethnicity.CONCLUSION:Serologic CD responses differ between HK Asian and Australian Caucasian patients.Different genetic,environmental or disease pathogenic factors may account for these differences.

Utility of serological markers in inflammatory bowel diseases: Gadget or magic?

The panel of serologic markers for inflammatory bowel diseases （IBD） is rapidly expanding. Although antiSaccharornyces cerev/siae antibodies （ASCA） and atypical perinuclear antineutrophil cytoplasmic antibodies （P-ANCA） remain the most widely investigated, an increasing amount of experimental data is available on newly discovered antibodies directed against various microbial antigens. The role of the assessment of various antibodies in the current IBD diagnostic algorithm is often questionable due to their limited sensitivity. In contrast, the association of serologic markers with disease behavior and phenotype is becoming increasingly well-established. An increasing number of observations confirms that patients with Crohn＇s disease expressing multiple serologic markers at high titers are more likely to have complicated small bowel disease （e.g. stricture and/or perforation） and are at higher risk for surgery than those without, or with low titers of antibodies. Creating homogenous disease sub-groups based on serologic response may help develop more standardized therapeutic approaches and may help in a better understanding of the pathomechanism of IBD. Further prospective clinical studies are needed to establish the clinical role of serologic tests in IBD.

Diagnosis of Crohn's disease in India where tuberculosis is widely prevalent

AIM:To define the parameters that positively predict diagnosis of Crohn's disease (CD) and differentiate it from gastrointestinal tuberculosis (GITB). METHODS:This prospective study over 3 years was carried out in the consecutive Indian patients with definite diagnosis of CD and equal numbers of patients with definite diagnosis of GITB. Demographic, clinical, laboratory, morphological and histological features were noted in all the patients. Serological tests such as p-ANCA, c-ANCA, IgA ASCA and IgG ASCA, were performed. Endoscopic biopsy and/or surgical tissue specimens were subjected to smear and culture for acid-fast bacilli (AFB) and tissue polymerase chain reaction for tuberculosis (TB PCR). Diagnosis of CD and GITB was based on the standard criteria. Data were analyzed using univariate Chi-square test and multiple logistic regression (MLR). RESULTS:The study is comprised of 26 patients with CD (age 36.6 ± 8.6 year, male:female, 16:10) and 26 patients with GITB (age 37.2 ± 9.6 year, male:female, 15:11). The following clinical variables between the two groups (CD vs TB) were significant in univariate analysis:duration of symptoms (58.1 ± 9.8 vs 7.2 ± 3.4 mo), diarrhoea (69.2% vs 34.6%), bleeding per rectum (30.7% vs 3.8%), fever (23.1% vs 69.2%), ascites (7.7% vs 34.6%) and extra-intestinal manifestations of inflammatory bowel disease (61.5% vs 23.1%). Of these, all except ascites and extra-colonic manifestations were found statistically significant by MLR. Accuracy of predicting CD was 84.62% based on the fever, bleeding P/R, diarrhoea and duration of symptoms while it was 63.4% when histology was reported as inflammatory bowel disease and 42.3% when there was recurrence of disease after surgery. Accuracy of predicting GITB was 73.1% when there was co-existing pulmonary lesions and/or abdominal lymphadenopathy;75% when tuberculosis was reported in histology;63.4% when granuloma was found in histology;82.6% when TB PCR was positive;and 61.5% when smear and/ or culture was positive for AFB. Serological test was not useful in differentiation of CD from GITB. Positivity rates for CD and GITB were:p-ANCA-3.8% and 3.8%, c-ANCA-3.8% and 0%, IgA ASCA-38.4% and 23.1%, and IgG ASCA-38.4% and 42.3%, respectively. CONCLUSION:Simple clinical parameters like fever, bleeding P/R, diarrhoea and duration of symptoms have the highest accuracy in differentiating CD from GITB.

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 firstdegree 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.

Serologic and laboratory markers in prediction of the disease course in inflammatory bowel disease

The search for biologic markers that can assess the natural history and perhaps predict the course of individual's disease including response to treatments over time has become an important focus of inflammatory bowel disease research.The knowledge of an individual's prognosis can help physicians and patients make important management decisions and aid communication on risk and benefits of disease and treatment.

Celiac disease and microscopic colitis:A report of 4 cases

Celiac disease (CD) is an autoimmune disorder of the small intestine that occurs in genetically predisposed people at all ages.However,it can be associated also to other immunopathological disorders,and may be associated with abnormal histology in segments of the gut other than the small bowel including colonic inflammation.While guidelines for endoscopic investigation of the jejunum are well defined,no indication is defined for colonic investigation.We describe four cases of concurrent CD and microscopic colitis (MC) diagnosed at our department over a 10-year period and analyzed the main features and outcomes of CD in this setting.The symptoms of these patients were improved initially by a gluten-free diet before the onset of MC symptoms.Two of the patients were siblings and had an atypical form of CD.The other two patients with CD and MC also presented with fibrosing alveolitis and were anti-Saccharomyces cerevisiae antibody positive.The co-existence of immune-mediated small bowel and colonic inflammatory and pulmonary diseases are not well-known,and no systematic approach has been used to identify the lifelong patterns of these immune-based diseases.Patients can develop,or present with CD at any stage in life,which can co-exist with other gastrointestinal diseases of (auto-) immune origin.In addition,the fa-milial co-existence and prevalence of MC in patients with a prior diagnosis of CD are unclear.Clinicians managing celiac disease should be aware of these associations and understand when to consider colon investigation.