Early primary biliary cholangitis is characterised by brain abnormalities on cerebral magnetic resonance imaging.

BACKGROUND: Brain change can occur in primary biliary cholangitis (PBC), potentially as a result of cholestatic and/or inflammatory processes. This change is linked to systemic symptoms of fatigue and cognitive impairment. AIM: To identify whether brain change occurs early in PBC. If the change develops early and is progressive, it may explain the difficulty in treating these symptoms. METHODS: Early disease brain change was explored in 13 patients with newly diagnosed biopsy-proven precirrhotic PBC using magnetisation transfer, diffusion-weighted imaging and 1 H magnetic resonance spectroscopy. Results were compared to 17 healthy volunteers. RESULTS: Cerebral magnetisation transfer ratios were reduced in early PBC, compared to healthy volunteers, in the thalamus, putamen and head of caudate with no greater reduction in patients with greater symptom severity. Mean apparent diffusion coefficients were increased in the thalamus only. No 1 H magnetic resonance spectroscopy abnormalities were seen. Serum manganese levels were elevated in all PBC patients, but no relationship was seen with imaging or symptom parameters. There were no correlations between neuroimaging data, laboratory data, symptom severity scores or age. CONCLUSIONS: This is the first study to be performed in this precirrhotic patient population, and we have highlighted that neuroimaging changes are present at a much earlier stage than previously demonstrated. The neuroimaging abnormalities suggest that the brain changes seen in PBC occur early in the pathological process, even before significant liver damage has occurred. If such changes are linked to symptom pathogenesis, this could have important implications for the timing of second-line-therapy use.

Type 1 autoimmune pancreatitis and IgG4-related sclerosing cholangitis is associated with extrapancreatic organ failure, malignancy, and mortality in a prospective UK cohort.

OBJECTIVES: Type I autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-related SC) are now recognized as components of a multisystem IgG4-related disease (IgG4-RD). We aimed to define the clinical course and long-term outcomes in patients with AIP/IgG4-SC recruited from two large UK tertiary referral centers. METHODS: Data were collected from 115 patients identified between 2004 and 2013, and all were followed up prospectively from diagnosis for a median of 33 months (range 1-107), and evaluated for response to therapy, the development of multiorgan involvement, and malignancy. Comparisons were made with national UK statistics. RESULTS: Although there was an initial response to steroids in 97%, relapse occurred in 50% of patients. IgG4-SC was an important predictor of relapse (P<0.01). Malignancy occurred in 11% shortly before or after the diagnosis of IgG4-RD, including three hepatopancreaticobiliary cancers. The risk of any cancer at diagnosis or during follow-up when compared with matched national statistics was increased (odds ratio=2.25, CI=1.12-3.94, P=0.02). Organ dysfunction occurred within the pancreas, liver, kidney, lung, and brain. Mortality occurred in 10% of patients during follow-up. The risk of death was increased compared with matched national statistics (odds ratio=2.07, CI=1.07-3.55, P=0.02). CONCLUSIONS: Our findings suggest that AIP and IgG4-SC are associated with significant morbidity and mortality owing to extrapancreatic organ failure and malignancy. Detailed clinical evaluation for evidence of organ dysfunction and associated malignancy is required both at first presentation and during long-term follow-up.

PSC, AIH and overlap syndrome in inflammatory bowel disease.

Primary sclerosing cholangitis (PSC) is a progressive, cholestatic disorder characterised by chronic inflammation and stricture formation of the biliary tree. Symptoms include pruritus, fatigue and in advanced cases ascending cholangitis, cirrhosis and end-stage hepatic failure. Patients are at an increased risk of malignancy arising from the bile ducts, gallbladder, liver and colon. The majority (>80%) of Northern European patients with PSC also have inflammatory bowel disease (IBD), usually ulcerative colitis (UC). IBD commonly presents before the onset of PSC, although the opposite can occur and the onset of both conditions can be separated by many years. The colitis associated with PSC is characteristically mild although frequently involves the whole colon. Despite the majority of patients having relatively inactive colonic disease, paradoxically the risk of colorectal malignancy is substantially increased. Patients may also develop dominant, stenotic lesions of the biliary tree which may be difficult to differentiate from cholangiocarcinoma and the coexistence of IBD may influence the development of this complication. Ursodeoxycholic acid may offer a chemoprotective effect against colorectal malignancy and improve liver biochemical indices. Evidence of any beneficial effect on histological progression of hepatobiliary disease is less clear. High doses (∼25-30 mg/kg/d) may be harmful and should be avoided. Autoimmune hepatitis (AIH) is less common in patients with IBD than PSC, however, an association has been observed. A small subgroup may have an overlap syndrome between AIH and PSC and management should be individualised dependant on liver histology, serum immunoglobulin levels, autoantibodies, degree of biochemical cholestasis and cholangiography.

A unique clinical phenotype of primary sclerosing cholangitis associated with Crohn's disease.

BACKGROUND AND AIMS: A distinct clinical phenotype has been demonstrated for ulcerative colitis with concomitant primary sclerosing cholangitis (PSC). The course and behaviour of Crohn's disease (CD) with PSC has, in contrast, never been defined. We aimed to define the characteristics of patients with concomitant PSC and CD. METHODS: The Oxford PSC and IBD databases were abstracted for: PSC subtype, date of diagnosis, symptom onset, smoking history, Mayo Clinic PSC score and outcomes (hepatic failure, liver transplantation, Montréal CD classification, treatment, cancer and death). Patients with PSC/CD were matched 1:2 to two control groups: one with PSC/UC and one with isolated CD. RESULTS: 240 patients with PSC were identified; 32 (13%) with CD, 129 (54%) with co-existing UC, and 79 had PSC without IBD. For PSC/CD vs. CD controls, isolated ileal CD was less common (6% vs. 31%, p=0.03). Smoking was less common in PSC/CD (13% vs. 34%, p=0.045). No difference in the distribution of CD, or treatment required was observed. For PSC/CD vs. PSC/UC controls, more patients with PSC/CD were female (50% vs. 28%, p=0.021). 22% of PSC/CD patients had small duct PSC compared with 6% with PSC/UC, (p=0.038). Major event-free survival was prolonged in the PSC/CD group compared with PSC/UC, (Cox regression p=0.04). CONCLUSION: Unlike PSC/UC, patients with PSC/CD were as likely to be female as male, more commonly had small duct PSC and less commonly progressed to cancer, liver transplantation, or death. Compared to patients with isolated CD, patients with PSC/CD were less likely to smoke or have ileal disease.

Systematic review: management options for primary sclerosing cholangitis and its variant forms - IgG4-associated cholangitis and overlap with autoimmune hepatitis.

BACKGROUND: Primary sclerosing cholangitis (PSC) remains a challenging disease to manage. The main goals are prevention of disease progression and reduction of the increased cancer risk. AIMS: To review the management strategies for PSC and its variant forms based on published studies. METHODS: Publications were identified using Pubmed, Medline and Ovid search engines. RESULTS: Distinguishing PSC from variants, such as IgG4-associated cholangitis, and overlap with autoimmune hepatitis is essential to guide treatment decisions. There is no proven efficacious medical treatment for PSC. Ursodeoxycholic acid has been disappointing in low and moderate doses, and potentially dangerous in higher doses, although its role and optimal dose in chemoprevention requires investigation. The novel bile acid, 24-norursodeoxycholic acid, has shown promise in mouse models; human trials are in progress. Dominant strictures are optimally managed by dilatation and stenting to relieve obstructive complications, although exclusion of biliary malignancy is essential. Liver transplantation is the only proven therapy for those with advanced disease. Cholangiocarcinoma remains the most unpredictable and feared complication. In highly selected groups, neo-adjuvant chemoradiation with liver transplantation seems promising, but requires further validation. Screening for inflammatory bowel disease and surveillance for colorectal carcinoma should not be overlooked. CONCLUSIONS: The effective management of PSC and its variants is hindered by uncertainties regarding pathogenesis of disease and factors responsible for its progression. Genome studies may help to identify further targets for drug therapy and factors leading to malignant transformation.

CXCR2 antagonists for the treatment of pulmonary disease.

Chemokines have long been implicated in the initiation and amplification of inflammatory responses by virtue of their role in leukocyte chemotaxis. The expression of one of the receptors for these chemokines, CXCR2, on a variety of cell types and tissues suggests that these receptors may have a broad functional role under both constitutive conditions and in the pathophysiology of a number of acute and chronic diseases. With the development of several pharmacological, immunological and genetic tools to study CXCR2 function, an important role for this CXC chemokine receptor subtype has been identified in chronic obstructive pulmonary disease (COPD), asthma and fibrotic pulmonary disorders. Interference with CXCR2 receptor function has demonstrated different effects in the lungs including inhibition of pulmonary damage induced by neutrophils (PMNs), antigen or irritant-induced goblet cell hyperplasia and angiogenesis/collagen deposition caused by lung injury. Many of these features are common to inflammatory and fibrotic disorders of the lung. Clinical trials evaluating small molecule CXCR2 antagonists in COPD, asthma and cystic fibrosis are currently underway. These studies hold considerable promise for identifying novel and efficacious treatments of pulmonary disorders.

Chemoprevention and screening in primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease that causes fibrosis of the biliary tree. Life expectancy of patients is reduced by liver failure and a high incidence of malignancy. It is closely associated with inflammatory bowel disease, particularly ulcerative colitis, which coexists in approximately three-quarters of northern European patients. Cancers include cholangiocarcinoma, gallbladder cancer, hepatocellular carcinoma, pancreatic cancer and colorectal cancer. Ursodeoxycholic acid appears to reduce the incidence of colorectal neoplasia in patients with PSC, and there is some suggestion that it may also reduce the incidence of cholangiocarcinoma. A chemoprotective benefit of 5-aminosalicylates has not been confirmed in patients with PSC with associated inflammatory bowel disease. There is no accepted screening programme for cholangiocarcinoma, but methods for detecting early disease using biochemical markers, scanning using positron emission tomography or MRI, and endoscopic procedures such as endosonography and endoscopic retrograde cholangiopancreatography are discussed. A combination of techniques is often used in an attempt to diagnose early cholangiocarcinoma. Cholecystectomy should be performed for gallbladder polyps, as many are malignant, and ultrasonography and alpha-fetoprotein testing are suggested for screening for hepatocellular carcinoma. Colorectal carcinoma screening should be performed after the diagnosis of PSC, and surveillance colonoscopy should be performed annually if there is concomitant colitis.

13C-methacetin-breath test compared to also noninvasive biochemical blood tests in predicting hepatic fibrosis and cirrhosis in chronic hepatitis C.

BACKGROUND: The (13)C-methacetin-breath test and also several noninvasive blood tests comprising routine laboratory parameters have been proposed to predict fibrosis and cirrhosis in chronic hepatitis C. The aim of the study was to compare the diagnostic accuracy between these tests referring to hepatic histology as gold standard. METHODS: 96 patients with chronic hepatitis C virus infection underwent percutaneous liver biopsy and the (13)C-methacetin-breath test. The Fibroindex, the aspartate aminotransferase to platelet ratio index , and the aspartate aminotransferase to alanine aminotransferase ratio were used as parameters for the staging of fibrosis. The main endpoint was the area under the characteristic curves for the diagnosis of advanced fibrosis (F3-F4) and cirrhosis (F4) according to the Batts Ludwig criteria. RESULTS: ROC analysis revealed a cut-off <14.6 per thousand best with 92.6% sensitivity and 84.1% specificity for the (13)C-methacetin-breath test, for the Fibroindex >1.82 70.4% sensitivity and 91.3% specificity, for the aspartate aminotransferase to platelet ratio >1.0 a 66.7% sensitivity and 75.4% specificity, and for the aspartate aminotransferase to alanine aminotransferase ratio >1.0 63.0% sensitivity and 59.4% specificity in predicting liver cirrhosis. The areas under the curve for the breath test, the Fibroindex, aspartate aminotransferase to platelet ratio and the aspartate aminotransferase to alanine aminotransferase ratio were 0.958, 0.845, 0.799, and 0.688, respectively, when predicting cirrhosis. For identifying patients with advanced fibrosis, the areas under the curve were 0.827, 0.804, 0.779, and 0.561, respectively. Discordances between Fibroindex (21%), aspartate aminotransferase to platelet ratio (29%) or aspartate aminotransferase to alanine aminotransferase ratio (37.6%) and liver biopsy were significantly more frequent than between (13)C-breath test (11.6%) and liver biopsy (P<0.05). CONCLUSION: The (13)C-methacetin-breath test is more reliable in predicting advanced fibrosis and cirrhosis than simple biochemical parameters (aspartate aminotransferase to platelet ratio; aspartate aminotransferase to alanine aminotransferase ratio).

Review article: current management of primary sclerosing cholangitis.

The management of primary sclerosing cholangitis (PSC) is hindered by incomplete understanding of the pathogenesis of the disease and the lack of good prognostic models. Few large randomized controlled trials of drug therapy have been published. Best practice in the management of PSC is currently based therefore on careful interpretation of the available evidence, close observation of individual patients and clinical experience of the disease. Drug therapy is useful for alleviating symptoms. Ursodeoxycholic acid may slow progression of the disease and reduce the frequency of complications. Consensus is emerging on the issues of screening for the malignant complications of PSC and the indications for liver transplantation are becoming broader and encompassing the earliest stages of cholangiocarcinoma. In view of the rarity of the disease in the general population, large international collaborations to study PSC are necessary to provide clearer answers in areas of uncertainty, and these are now beginning to emerge.

Role of CXCR2 in cigarette smoke-induced lung inflammation.

It has been hypothesized that the destruction of lung tissue observed in smokers with chronic obstructive pulmonary disease and emphysema is mediated by neutrophils recruited to the lungs by smoke exposure. This study investigated the role of the chemokine receptor CXCR2 in mediating neutrophilic inflammation in the lungs of mice acutely exposed to cigarette smoke. Exposure to dilute mainstream cigarette smoke for 1 h, twice per day for 3 days, induced acute inflammation in the lungs of C57BL/6 mice, with increased neutrophils and the neutrophil chemotactic CXC chemokines macrophage inflammatory protein (MIP)-2 and KC. Treatment with SCH-N, an orally active small molecule inhibitor of CXCR2, reduced the influx of neutrophils into the bronchoalveolar lavage (BAL) fluid. Histological changes were seen, with drug treatment reducing perivascular inflammation and the number of tissue neutrophils. beta-Glucuronidase activity was reduced in the BAL fluid of mice treated with SCH-N, indicating that the reduction in neutrophils was associated with a reduction in tissue damaging enzymes. Interestingly, whereas MIP-2 and KC were significantly elevated in the BAL fluid of smoke exposed mice, they were further elevated in mice exposed to smoke and treated with drug. The increase in MIP-2 and KC with drug treatment may be due to the decrease in lung neutrophils that either are not present to bind these chemokines or fail to provide a feedback signal to other cells producing these chemokines. Overall, these results demonstrate that inhibiting CXCR2 reduces neutrophilic inflammation and associated lung tissue damage due to acute cigarette smoke exposure.

Fatigue in patients with primary sclerosing cholangitis.

BACKGROUND: The occurrence of fatigue in primary sclerosing cholangitis (PSC), its impact on quality of life and the role of concomitant inflammatory bowel disease (IBD) and coexisting irritable bowel syndrome (IBS) is unexplored. METHODS: Ninety-three patients with PSC, associated with IBD in 80% of cases and 77 patients with IBD alone, were enrolled in the study. The patients completed the following questionnaires: the Fatigue Impact Scale (FIS), the Psychological General Well-Being Index (PGWB), the Gastrointestinal Symptom Rating Scale (GSRS), the Beck Depression Inventory (BDI) and diagnostic criteria for IBS. Questionnaire data were related to liver tests and the latest liver biopsy in the PSC patients. Two sex- and age matched controls from the general population (GP) were assigned to each PSC patient and these controls completed the FIS and the BDI. RESULTS: Total fatigue score did not differ significantly between patients with PSC and IBD alone. Median total fatigue score among GP subjects was 39 (13-72), which was higher than in PSC (19 (6-52) (P = 0.02)) and in IBD patients (19 (5-35) (P < 0.0001)). PGWB and GSRS scores did not differ between patients with PSC and IBD alone. Depression and general health (PGWB) were independent predictors for total fatigue score in PSC. No correlation was observed between fatigue in PSC and the severity of the liver disease. CONCLUSIONS: Fatigue in patients with PSC is related to depression but not to the severity of the liver disease. Both the PSC and IBD patients had lower total fatigue scores than subjects from the general population. This argues against fatigue as a specific symptom of PSC and IBD patients.

The effects of body fat on pulmonary function and gas exchange in cynomolgus monkeys.

Obesity adversely affects lung function in humans often reducing arterial blood oxygenation. To determine if obesity adversely affects lung function in cynomolgus monkeys, which is a species that is often used for pulmonary research, pulmonary mechanics, ventilation, functional residual capacity (FRC), and arterial blood gases were measured using spontaneous respiration and on mechanical ventilation with room air or 100% O(2). Body fat percentage was measured by dual energy X-ray absorption. Blood leptin levels were measured by radioimmune assay. Obese monkeys breathed faster with lower tidal volume, but pulmonary resistance and dynamic lung compliance did not change with body fat. FRC and blood leptin were, respectively, negatively and positively correlated with percent body fat. FRC correlated moderately with ventilatory parameters and strongly with arterial oxygen tension, alveolar-arterial oxygen difference and venous admixture. Therefore, obesity in cynomolgus monkeys had marked, deleterious effects on FRC, ventilation and arterial oxygenation. Obesity may be an important confounding variable in lung function studies in primates.

Inhibition of experimental acute pulmonary inflammation by pirfenidone.

Pirfenidone, a putative tumor necrosis factor-alpha (TNF-alpha) inhibitor, has recently gained recognition for its therapeutic use in the treatment of idiopathic pulmonary fibrosis. As pulmonary fibrosis may be the result of lung inflammatory processes, we examined the anti-inflammatory potential of pirfenidone in several models of acute pulmonary inflammation. In antigen-induced allergic paradigms, 24 h after antigen challenge, sensitized mice or guinea pigs develop a prominent pulmonary inflammation, reflected by a significant increase in the number of recoverable bronchoalveolar lavage (BAL) total cells and eosinophils. In both species, the pretreatment of animals with pirfenidone (10 and 30 mg/kg) resulted in a dose-dependent inhibition of the antigen-induced pulmonary inflammation, which was reflected by a significant decrease in the BAL eosinophils and total cells by the 30 mg/kg dose. In a non-allergic model of pulmonary inflammation, rats challenged with intratracheal LPS develop a significant increase in BAL neutrophils and total cells, along with significant increases in TNF-alpha and IL-6. Pretreatment with pirfenidone (3 and 30 mg/kg) showed a dose-dependent inhibition of the LPS-induced pulmonary inflammation, reflected by a significant decrease in the number of BAL total and neutrophilic cells at both the 3 and 30 mg/kg dose. However, pirfenidone had no effect on the peak BAL levels of TNF-alpha. In contrast, pirfenidone significantly inhibited BAL levels of IL-6. In summary, we have shown that pirfenidone can inhibit allergic and non-allergic inflammatory cell recruitment and that its pulmonary anti-inflammatory activity is independent of TNF-alpha inhibition.

Patients with small duct primary sclerosing cholangitis have a favourable long term prognosis.

BACKGROUND: Patients with cholestatic liver function tests and histological features of primary sclerosing cholangitis (PSC) but a normal cholangiogram are considered to have small duct PSC. The natural history of this condition is unknown. METHODS: Thirty three patients with small duct PSC were identified among patients admitted for diagnostic workup of cholestatic liver function tests in one centre in the UK (Oxford) and one centre in Norway (Oslo). A total of 260 patients with large duct PSC were compared, and prognosis in terms of death, cholangiocarcinoma, biochemical features, histological features, and symptoms analysed. RESULTS: Mean age at diagnosis was 38 years and 39 years in small duct and large duct PSC, respectively. Mean follow up was 106 months in small duct and 105 months in large duct patients. Four patients originally considered to have small duct developed large duct PSC. Two of these underwent liver transplantation during follow up. Of the remainder who did not develop large duct PSC, two patients died during follow up: one of liver failure and the other of cardiac death unrelated to her liver disease. A total of 122 (47%) large duct patients either required liver transplantation (34 patients) or died (88 patients). Small duct patients had a significantly better survival compared with large duct patients. Among small duct patients, none developed cholangiocarcinoma compared with 28 of 260 (11%) large duct patients. CONCLUSIONS: Patients with small duct PSC seem to have a good prognosis in terms of survival and development of cholangiocarcinoma. Small duct PSC progresses to large duct PSC in a small proportion of patients.

Cigarette smoking, appendectomy, and tonsillectomy as risk factors for the development of primary sclerosing cholangitis: a case control study.

BACKGROUND AND AIMS: The strong clinical association between primary sclerosing cholangitis (PSC) and ulcerative colitis (UC) suggests common factors in their pathogenesis. Smoking, previous appendectomy, and tonsillectomy have been associated with a decreased risk of developing UC. In this study, our aim was to examine these risk factors in patients with PSC with and without underlying inflammatory bowel disease (IBD). METHODS: The smoking habits and history of previous appendectomy and/or tonsillectomy of 170 patients with PSC, 41 without underlying IBD, 170 patients with UC but normal liver function tests, and 170 age and sex matched community controls were obtained by questionnaire. RESULTS: A total of 112 PSC patients (66%) had never smoked compared with 66 controls (39%). Only 12 PSC patients (7%) were current smokers versus 43 controls (25%). The resultant odds ratio of having PSC was 0.17 (95% confidence interval (CI) 0.08-0.35) among current smokers and 0.33 (95% CI 0.21-0.52) among ever (former+current) smokers. Among former smokers, the odds of having PSC were also significantly decreased (odds ratio 0.45, 95% CI 0.26-0.73; p<0.05). In the subgroup of PSC patients without IBD, only 5% were current smokers versus 26% of matched controls, and never smokers were overrepresented (68% v 37%). The rate of previous appendectomy was similar in all three study groups (14%, 12%, and 13%) but the frequency of tonsillectomy was reduced in the PSC group (21% v 31%; p=0.05). CONCLUSION: PSC, like UC, is a disease of non-smokers as the odds of having PSC was significantly decreased among current and former smokers. The association between non-smoking and PSC was independent of whether the PSC patient had underlying IBD. Previous tonsillectomy but not appendectomy may also be associated with a decreased risk of PSC but this warrants further study.

A preliminary trial of high-dose ursodeoxycholic acid in primary sclerosing cholangitis.

BACKGROUND & AIMS: Ursodeoxycholic acid (UDCA) is used for the treatment of cholestatic liver diseases including primary biliary cirrhosis (PBC) for which it has a positive effect on laboratory values, may delay the development of liver failure and prolong the transplant-free disease period. Standard doses of UDCA (8-15 mg/kg daily) have been shown to be ineffective in the treatment of primary sclerosing cholangitis (PSC). We report on the findings (clinical, biochemical, histological, and cholangiographic) and side effects of a 2-year double-blind placebo-controlled preliminary study of high-dose UDCA in PSC patients. METHODS: Twenty-six patients with PSC were randomized to high-dose (20 mg/kg daily) UDCA or placebo. Cholangiography and liver biopsy were performed at entry and after 2 years. Symptoms, clinical signs, and liver biochemical tests were recorded at 3 monthly intervals. RESULTS: High-dose UDCA did not influence symptoms, but there was a significant improvement in liver biochemistry (serum alkaline phosphatase, P = 0.03; gamma-glutamyl transferase, P = 0.01) and a significant reduction in progression in cholangiographic appearances (P = 0.015) and liver fibrosis as assessed by disease staging (P = 0.05). In the treatment group, a significant increase in total bile acids and saturation with UDCA >70% confirmed patient compliance. No significant side effects were reported. CONCLUSIONS: High-dose UDCA may be of clinical benefit in PSC, but trials with a larger number of participants and of longer duration are required to establish whether the effect of high-dose UDCA on liver biochemistry, histology, and cholangiography in patients with PSC is translated into improved long-term survival.

Evaluation of serologic disease markers in a population-based cohort of patients with ulcerative colitis and Crohn's disease.

BACKGROUND: The sensitivity of assays for antineutrophil cytoplasmic antibody (ANCA), anti-Saccharomyces cerevisiae antibody (ASCA), and antipancreatic antibody (PAB) in different laboratories is unknown. Likewise, the sensitivity and diagnostic usefulness of these assays in patients with inflammatory bowel disease (IBD) in the community is unknown. METHODS: An incidence cohort of 290 patients with IBD were offered participation in the study. Blood was obtained from 162 patients (56%) (83 with ulcerative colitis, 79 with Crohn's disease) who agreed to participate. ANCA was determined in five laboratories. ASCA in two laboratories, and PAB in one laboratory. RESULTS: In ulcerative colitis, the sensitivity of ANCA determined in five laboratories varied widely, ranging from 0-63%. In Crohn's disease, the sensitivity of ASCA determined in two laboratories did not vary significantly, ranging from 39-44%; and the sensitivity of PAB determined in one laboratory was 15%. The optimal diagnostic usefulness was obtained from one laboratory where the positive predictive values of a positive ANCA assay combined with a negative ASCA assay for ulcerative colitis, and a negative ANCA combined with a positive ASCA for Crohn's disease, were 75% and 86%, respectively. CONCLUSIONS: In patients with IBD, the sensitivity of ANCA varied widely in different laboratories, whereas the prevalence of ASCA was similar. The positive predictive values of the ANCA assay combined with the ASCA assay for ulcerative colitis and Crohn's disease are high enough to be clinically useful.