Long-term evolution of disease behavior of Crohn's disease

Effect of systemic corticosteroid therapy on risk for intra-abdominal or pelvic abscess in non-operated Crohn's disease

BACKGROUND & AIMS

Systemic corticosteroid therapy increases risk of postoperative sepsis in Crohn's disease. This study investigates its effect on risk for sepsis in non-operated patients.

METHODS

A retrospective case-control study was performed in 432 patients with Crohn's disease (the 94% of our database for whom adequate documentation could be retrieved). Two analyses were performed. The first tested the hypothesis that patients with perforating Crohn's disease (n = 86) were more likely to develop intra-abdominal or pelvic abscess (n = 29) if they had received systemic corticosteroids during the previous 3 months. The second analysis, confined to interventions since 1998, tested the hypothesis that corticosteroid therapy was more common during the 3 months before presentation with intra-abdominal or pelvic abscess (n = 12) than during the 3 months after presentation with a relapse of nonperforating disease (n = 24 consecutive patients). In both analyses adjustment was made for any other significant variable.

RESULTS

Systemic corticosteroid therapy was associated with an adjusted odds ratio (OR) for intra-abdominal or pelvic abscess of 9.03 (95% confidence interval [CI], 2.40-33.98) in patients with perforating Crohn's disease. Patients receiving prednisolone > or = 20 mg per day had an OR of 2.81 (95% CI, 0.99-7.99) for abscess compared with those receiving a lower dose. In patients with relapsed active disease, corticosteroid therapy was associated with an unadjusted OR of 9.31 (95% CI, 1.03-83.91) for intra-abdominal or pelvic abscess. Neither smoking nor azathioprine usage was associated with increased risk for abscess.

CONCLUSIONS

Systemic corticosteroid therapy for Crohn's disease is associated with increased risk for intra-abdominal or pelvic abscess.

Intestinal perforation in Crohn's disease

New medical therapeutic options challenge the usual surgical management of Crohn's disease patients with intestinal perforation.

OBJECTIVES

To determine factors predictive of surgery for perforation in Crohn's disease and define a group of patients that may benefit from non-surgical treatment.

METHODS

One hundred and sixty-two patients (69 males, 93 females, mean age 39) with perforated Crohn's disease (fistula, abscess, inflammatory mass) between January 1995 and September 2003 were studied retrospectively.

RESULTS

One hundred and fifty-one patients (93%) underwent surgery: 70 had planned surgery and 81 had surgery for symptomatic deterioration. At two years, the cumulative probability of intestinal resection was 0.89 +/- 0.03, and the cumulative probability of unplanned intestinal resection was 0.72 +/- 0.05. Predictive factors of unplanned surgery were elevated platelet count (adjusted hazard ratio 3.15; 95% CI 2.21-4.50) and absence of fistula (adjusted hazard ratio 3.14; 95% CI 2.48-3.99). The rate of postoperative complications, the need for a stoma, and the length of bowel resection were not significantly different whether the surgery was planned or not.

CONCLUSION

A significant proportion of patients with intestinal perforation complicating Crohn's disease, particularly those with a fistula, might benefit from non-surgical treatment.

Polymorphism of the heat-shock protein gene Hsp70-2, but not polymorphisms of the IL-10 and CD14 genes, is associated with the outcome of Crohn's disease

OBJECTIVE

In Crohn's disease (CD) a Th-1 dominant immune reaction is induced, which could be associated with genetic predisposition. Several previous studies have investigated the roles of CD14, heat-shock protein (Hsp)70 and IL-10 gene polymorphisms in the development of the disease. The results are contradictory and inter-racial differences are implicated. Therefore, this phenomenon was evaluated in well-documented Caucasian patients with CD in order to verify the clinical importance of these polymorphisms.

MATERIAL AND METHODS

The genomic DNA of 133 patients with CD and that of 75 healthy controls were examined. CD was divided into subgroups according to the Vienna classification. An arbitrary classification system based on disease severity was also applied, which was determined according to the therapeutic intervention. The CD14 (-159 C-->T) promoter gene polymorphism was investigated by melting-point analysis. The IL-10 (-1082 G-->A) and Hsp70-2 (1267 A-->G) gene polymorphisms were detected by RFLP (restriction fragment length polymorphism).

RESULTS

None of the allele frequencies of the examined polymorphisms differed significantly between the patient and control populations. Neither the CD14 nor the IL-10 polymorphisms exhibited any correlation with the development or with the progression of the disease. With regard to Hsp70-2 gene polymorphism, those patients who carry at least one A allele have a significantly lower probability of the need for surgical intervention.

CONCLUSIONS

Allele A of the Hsp70-2 gene may be associated with a less severe form of CD, suggesting the clinical value of the genotype assessment. The genetic determination of the defense mechanisms in CD appears to be associated with the polymorphism of the Hsp70-2 gene rather than that of the CD14 or IL-10 genes.

Age-dependent phenotypic clinical expression of Crohn's disease

Crohn's disease is a heterogeneous disorder that involves different sites along the length of the gastrointestinal tract. It is usually characterized by a high rate of strictures and penetrating complications. The present study used the modified Vienna classification schema to explore the specific role of age at diagnosis on both disease location and disease behavior. There were 1,015 consecutively evaluated patients, including 449 males and 566 females. Disease was most often localized in the ileocolon and could be most often classified as complex disease (ie, in >70%) with strictures or penetrating complications. For both males and females, with increasing age at diagnosis, disease became less extensive, more often localized in the colon alone, and disease behavior could be characterized as more complex, especially with penetrating disease complications. These results demonstrate the phenomenon of age dependence in the phenotypic clinical expression of Crohn's disease.

Colonic Crohn's disease in children does not respond well to treatment with enteral nutrition if the ileum is not involved

Data supporting a response to treatment with exclusive enteral nutrition in pediatric colonic Crohn's disease are few. We examined clinical and biochemical responses of ileal, colonic, and ileocolonic Crohn's disease and assessed the endoscopic and histological colonic mucosal response in the colonic and ileocolonic groups. We prospectively enrolled 65 children (age: 8-17 years) with acute intestinal Crohn's disease (Pediatric Crohn's Disease Activity Index [PCDAI] >20). After ileocolonoscopy, gastroscopy, and a barium meal and follow-through, they were distributed into three groups (ileal, n = 12, ileocolonic, n = 39; and colonic, n = 14). All patients received exclusive polymeric feed as treatment, with a repeat endoscopy at completion of treatment. At enrollment the ileal group had significantly less severe disease (P = 0.05) compared to the colonic and ileocolonic groups. However, the colonic disease group showed the least fall in PCDAI scores at completion of treatment with enteral nutrition (P = 0.03), with the lowest remission rate (50%, vs 82.1% in the ileocolonic and 91.7% in the ileal group [chi2 test, P = 0.021]). Endoscopic and histologic colonic mucosal assessment showed a post-treatment improvement in the ileocolonic (P < or = 0.01) but not in the colonic disease group (P = ns). Children with disease in the colon respond better to enteral nutrition if the ileum is also involved. This may be due to different underlying inflammatory mechanisms. Detailed pretreatment assessment in studies of Crohn's disease according to disease distribution with appropriate individualized tailoring of treatment may be important in this regard.

Intra- and interobserver variation in the use of the Vienna classification of Crohn's disease

BACKGROUND

Crohn's disease is a heterogeneous disease, and several classification systems have been developed to classify the patients in more homogeneous groups. Our aim was to assess the intra- and interobserver variation when classifying patients according to the widely used Vifenna classification.

METHODS

Ten randomly selected Crohn's disease cases were presented to 11 Danish gastroenterologists with a special interest in inflammatory bowel diseases. Clinical details, together with endoscopic, radiologic, and pathologic reports, were presented to the participants as a PowerPoint slide show, sent by e-mail with a data collection form. The experts were asked to classify the cases according to the Vienna classification and to evaluate intraobserver variation; the participants classified the patients 3 times. The strength of agreement was calculated using kappa statistics.

RESULTS

Classification of the patients according to age gave a kappa value of 1.00. The intraobserver kappa value was good, with an average kappa value of 0.75 (range, 0.42-0.86) for location and 0.77 (range, 0.53-1.00) for behavior. The mean overall interobserver kappa value was 0.64 (range, 0.12-1.00), which improved slightly between the first and third rounds. When classifying according to location and behavior, most patients were classified in 2 or 3 different ways, and in no patients was there full agreement among the observers for both location and behavior.

CONCLUSIONS

In this study, we found an overall good interobserver agreement when using the Vienna classification, although when looking at individual cases, there was some disagreement.

The role of Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms and CARD15/NOD2 mutations in the susceptibility and phenotype of Crohn's disease

BACKGROUND

We investigated the influence of 2 common Toll-like receptor 4 (TLR4) polymorphisms on susceptibility and disease characteristics of Crohn's disease (CD).

METHODS

Genomic DNA from 204 patients with CD and 199 unrelated controls was analyzed for the presence of 2 single nucleotide polymorphisms in the TLR4 gene, resulting in the amino acid substitutions Asp299Gly and Thr399Ile. In addition, the carrier status for the 3 common CD-associated CARD15/NOD2 gene mutations, Arg702Trp, Gly908Arg, and 1007fs, was determined. The frequency of the different genotypes was compared, and a detailed genotype-phenotype correlation was performed.

RESULTS

An almost 2-fold increase in the frequency of the TLR4 Asp299Gly phenotype was observed in patients with CD (14.2%) compared with healthy controls (7.5%, P = 0.038, odds ratio = 2.03). The prevalence of a stricturing phenotype was increased in patients heterozygous for 1 of the TLR4 polymorphisms studied (Asp299Gly, 34.5%; Thr399Ile, 36.7%) compared with patients with wild-type TLR4 (17.1% and 16.7%; P = 0.04 and 0.02, respectively). The presence of the Asp299Gly polymorphism in the absence of CARD15/NOD2 mutations was a particularly strong predictor of the stricturing disease phenotype that was present in 47.4% of the patients with Asp299Gly+/NOD2- compared with 10.1% of the patients with the Asp299Gly-/NOD2+ status (P = 0.0009; P = 0.0004 for Thr399Ile+/NOD2- versus Thr399Ile-/NOD2+). In contrast, there was a trend toward a higher prevalence of the penetrating phenotype in the TLR4-/NOD2+ group (71.6%) compared with the TLR4+/NOD2- group (47.4%, P = 0.059).

CONCLUSIONS

The TLR4 Asp299Gly polymorphism is a risk factor for CD. TLR4 and CARD15/NOD2 mutations may contribute to distinct disease phenotypes.

Predictors of response to infliximab in luminal Crohn's disease

AIMS

To identify predictive factors of response to infliximab in luminal Crohn's disease (CD).

PATIENTS AND METHODS

All consecutive patients with luminal CD treated with infliximab between October 1999 and March 2003 in Bordeaux's referral centers were included. All had at least 3 months follow-up post infliximab infusion and no prior treatment with infliximab. Response rates were determined 2 and 8 weeks after infusion according to Crohn's Disease Activity Index (CDAI) (remission=CDAI<150 and response=CDAI decrease more than 100).

RESULTS

Among 44 patients (33 female; mean age 35 +/- 14 yr.), 39 (88%) had a clinical response 2 weeks after infusion (79% in remission). At week 8, the rate of response was 61.4% and exclusive colonic involvement predicted sustained response to treatment (P=0.03). The probability of remission at 56 weeks was 21.4%. Multivariate analysis demonstrated that the only factor associated with response duration was initiating immunosuppressive (IS) therapy in women (RR=3.61 95%CI[1.25-10.41], P=0.017).

CONCLUSION

Exclusive colonic involvement is the only predictive factor of sustained response to infliximab in luminal CD. At the time of infliximab infusion, initiation or modification of IS therapy may favor sustained response, at least in women.

Increased rates of early adverse reaction to azathioprine in patients with Crohn's disease compared to autoimmune hepatitis: a tertiary referral center experience

OBJECTIVES

Idiosyncratic drug hypersensitivity may occur at increased rates in specific patient populations. Azathioprine has a significant early adverse reaction (EAR) profile, which includes an acute syndrome of constitutional symptoms, fever, rash, and acute pancreatitis and often requires discontinuation of drug. EAR precludes azathioprine use in patients with Crohn's disease (CD) and autoimmune hepatitis (AIH). Our aims were to investigate differential rates of EAR to azathioprine in CD compared to AIH in a tertiary referral center population.

METHODS

Retrospective chart review of consecutive CD and AIH patients who were initiated on azathioprine in our inflammatory bowel disease (IBD) and hepatology centers was performed. EAR (fevers and constitutional symptoms, severe arthralgias, nausea, and vomiting) were defined as those occurring within 1 month of initiation. EAR rates between AIH and CD patients were compared using the Fisher's exact test.

RESULTS

One hundred and forty-three CD (88F/55M; age 39.2 +/- 13 yr) and 40 AIH (35F/5M; age 53.1 +/- 14 yr) patients were studied. All patients were initiated with equivalent azathioprine dosage (50 mg qd). All AIH patients were on prednisone (mean daily dose 7.5 mg) compared to 51% of CD patients (median daily dose 20 mg). EAR rates were significantly higher in CD patients (42/143; 29%) compared to AIH (2/40; 5%) (Fisher's exact test; p= 0.008). EAR excluding nausea and vomiting were still significantly higher in CD patients (27/143; 19%) compared to AIH (1/40; 2.5%) (Fisher's exact test; p= 0.01). All patients with EAR required drug discontinuation and 7% of CD patients required hospitalization for management of these complications.

CONCLUSIONS

CD patients represent a unique subgroup at increased risk of EAR to azathioprine. Mechanisms behind these reactions need to be further defined.

Crohn's disease patient characteristics in a tertiary referral center: comparison with patients from a population-based cohort

OBJECTIVES

Data on the clinical presentation, effects of therapy and prognosis of patients with Crohn's disease are often based on patients from specialized referral centers. We assessed the extent of the selection based on the clinical and demographic characteristics.

METHODS

All patients with Crohn's disease presenting to the University Hospital of Regensburg (Medical Department) were analyzed retrospectively with respect to demographic and disease specific characteristics. Only patients diagnosed <2 years before presentation were included in the main analysis. The original data from a population-based, prospectively assembled incidence cohort were available for comparison (EC-IBD, northern centers only, n=475). Age at diagnosis, disease location and behavior were categorized according to the Vienna classification. Differences were examined using chi-square tests.

MAIN RESULTS

At the referral center, 394 patients were treated within a 5-year period. Of these, 116 patients fulfilled the inclusion criteria for the comparative analysis. Sixteen percent of the referral patients were diagnosed at age 40 or older, as compared with 32% in the population-based group (P<0.004). The distribution of disease location, sex, smoking behavior and positive family history was similar in both groups. Among the referral patients, more had fistulas (39% versus 20%, P<0.001). Also, more patients were receiving steroids (49% versus 27%) or other immunosuppressive therapy (12% versus 4%). The selection effects increase with duration of disease.

CONCLUSIONS

Patients with late onset of disease, inflammatory only disease behavior and no need for immunosuppression are under-represented at a tertiary referral center.

Can we alter the natural history of Crohn disease in children?

The natural history of Crohn disease is characterized by recurrent bouts of active disease, the consequences of which can severely impair sufferers' physical and social functioning. Not only does the illness cause day-to-day morbidity for children but the consequence of the chronic inflammatory process also commonly results in the need for major intestinal surgery. The present challenge facing physicians treating children with Crohn disease is to alleviate symptoms and prolong periods of remission via the use of specifically targeted therapies while minimizing toxicity and promoting normal growth and development. Although systemic corticosteroids are effective in inducing clinical remission, they are of little or no benefit in maintaining remission and can contribute to linear growth retardation. Immunomodulating drugs such as azathioprine, 6-mercaptopurine and methotrexate have proved effective for inducing and maintaining remission of active Crohn disease. These agents are now commonly prescribed in children at diagnosis, after a severe attack or after surgery or in those who become corticosteroid-dependent or corticosteroid-resistant. Their use is not without potential adverse effects and not all patients respond well to these agents. With the introduction of biologic agents, notably the tumor necrosis factor-alpha monoclonal antibody infliximab, progress has been made in targeting specific pathogenetic mechanisms of Crohn disease and potentially altering the underlying disease process. Published experience in children is currently limited, but infliximab has been shown to improve symptoms and achieve corticosteroid independence in this age group. Unresolved issues with infliximab and other emerging biologic agents, including long-term safety, necessitate a degree of caution in selecting appropriate patients for treatment and with careful monitoring of their effects. The collection of contemporary natural history data is crucial to facilitate the better integration of current and emerging therapies in an attempt to alter the natural history of Crohn disease in children.

Medical Therapy of Crohn's Disease

There is no medical or surgical treatment that provides a permanent cure for Crohn's disease (CD). However, an evolving understanding of the pathogenesis of CD has provided clinicians with a diversity of medical treatment options for the disease. The goal of therapy is to induce and maintain clinical remission. The efficacy of immune-modifying agents such as azathioprine/6-mercaptopurine and infliximab have supported a paradigm shift in CD treatment in which maintenance agents are introduced earlier in the disease course. At the same time, it is imperative to balance the efficacy, safety, and tolerability of medical therapy. Given the variable and relapsing clinical course of CD, the physician and patient should ideally develop an ongoing relationship that allows for individualization of treatment regimens, monitoring of response and side effects, and modification of the therapeutic strategy in the absence of improvement.

Impact of the increasing use of immunosuppressants in Crohn's disease on the need for intestinal surgery

BACKGROUND/AIM

Immunosuppressants are now used much earlier in the course of Crohn's disease; however their effect on the natural history of the disease, especially on the need for surgery, is not known. The aim of this study was to assess the evolution of the need for surgery in Crohn's disease during the last 25 years.

PATIENTS AND METHODS

The medical charts of 2573 patients were reviewed retrospectively. The use of immunosuppressants (azathioprine or methotrexate), the need for intestinal resection, and the occurrence of intestinal complications were assessed using Kaplan-Meier analysis in five consecutive cohorts of patients defined by the date of diagnosis of Crohn's disease (1978-82; 1983-87; 1988-92; 1993-97; 1998-2002).

RESULTS

In 565 patients seen in the authors' unit within the first three months after diagnosis, characteristics of Crohn's disease at diagnosis did not differ from one cohort to another. The five year cumulative probability to receive immunosuppressants increased from 0 in the 1978-82 cohort to 0.13, 0.25, 0.25, and 0.56 in the 1983-87, 1988-92, 1993-97, and 1998-2002 cohorts, respectively (p<0.001). Concomitantly, the cumulative risk of intestinal resection remained unchanged (from 0.35 to 0.34 at five years; p=0.81). The cumulative risk of developing a stricturing or a penetrating intestinal complication remained also unchanged. Similar results were obtained in the 2008 patients seen during the same period who were referred to us more than three months after diagnosis.

CONCLUSION

Although immunosuppressants have been used more frequently over the last 25 years, there was no significant decrease of the need for surgery, or of intestinal complications of Crohn's disease.

Association of antibodies to exocrine pancreas with subtypes of Crohn's disease

OBJECTIVES

The Vienna classification of Crohn's disease (CD) subdivides patients according to their age at diagnosis, disease location, and disease behaviour. This study tested whether antibodies against exocrine pancreatic tissue (PAbs) are associated with Vienna classification subtypes of CD.

METHODS

PAbs were examined by indirect immunofluorescence in sera of patients with CD (n = 208), or ulcerative colitis (n = 47), and in normal controls (n = 50). Presence of PAbs was compared to the Vienna classification, disease activity, and drug therapy.

RESULTS

PAbs were present in 60 CD patients (28.8%), but in no patient with ulcerative colitis or in controls (P < 0.001). There was no significant association between PAbs and disease activity, or drug therapy. Complete classification into Vienna subtypes was possible in 168 patients. There was significant heterogeneity in PAb prevalence in these CD subtypes (P < 0.01). Variation was found in the behaviour category (B1, non-stricturing, non-penetrating CD: 14.0% PAb-positive; B2, stricturing CD: 41.7%; B3, penetrating CD: 31.5%; P = 0.02), but not age or location categories. PAbs were associated with long disease duration (P = 0.04).

CONCLUSION

This study confirms that PAbs are highly specific for CD. The small differences in their prevalence in CD subtypes do not suggest that PAb detection is useful in discrimination of CD phenotypes.

Clinical implications of inflammatory bowel disease genetics on phenotype

The genetic revolution has been with us for over a decade now. We have yet to see this impacting the care of patients except in a few rare examples. However, progress has been made in the field of inflammatory bowel disease (IBD) that could soon be translated to the bedside, both in terms of predicting the disease course as well as in the response to therapy. IBD traditionally has been classified as ulcerative colitis and Crohn's disease, with 10% of patients classified as having indeterminate colitis on the basis of clinical, radiologic, endoscopic, and histologic findings. However, this traditional view is now being challenged. Developments in genetics and serological markers, as well as an appreciation of the disease course, have led to an understanding that IBD is a heterogeneous group of diseases with some common genetic and environmental factors but different clinical manifestations in terms of disease behavior, location, and response to treatment. Data are now emerging that may allow us to more objectively select the correct therapy for the correct patient, rather than the current approach, which is based on clinical experience backed up by a less-than-perfect evidence base. In this article, we will review the evidence for this.

Outcome of patients with nonstenotic, nonfistulizing Crohn's disease

The nonstenotic, nonfistulizing (or inflammatory) pattern of Crohn's disease appears to be unstable in time and may evolve toward either the stenotic or the fistulizing pattern. We aimed to assess the course of the inflammatory disease and its relation to certain clinical characteristics. After a mean follow-up of 93 months, we evaluated 73 patients with an inflammatory pattern. The behavior trend and its relation to disease location, initial treatment, and need for corticosteroids, immunosuppressors, and surgical resection were analyzed. In 64% of the patients the inflammatory pattern did not change, while in 14 and 22% it evolved toward a stenotic and a fistulizing pattern, respectively. This change was mainly determined by the appearance of perianal disease (75%). The mean time to behavior evolution was 67 months. Most patients required corticosteroids (92%). Need for immunosuppressors (48%) and surgical resection (30%) was significantly greater (P < 0.05) among patients with a change in pattern than in those with persistent inflammatory disease. The inflammatory pattern of CD remains stable in about half of patients. The course of this pattern is not indolent, however, since the needs for immunosuppression and surgical resection during follow-up are considerable.

Disease location, anti-Saccharomyces cerevisiae antibody, and NOD2/CARD15 genotype influence the progression of disease behavior in Crohn's disease

BACKGROUND

Crohn's disease (CD) is characterized by heterogeneity of phenotype. The Vienna classification can be used to classify CD, and recent data illustrate that behavior evolves over the course of the disease. Clinical and biological influences on disease progression remain unclear. We examined the associations of CD disease progression at diagnosis and for up to 20 years of follow-up.

METHODS

Two hundred thirty-one well-characterized CD patients were studied. Demographic, clinical, and NOD2/CARD15 data were collected. Disease behavior according to the Vienna classification was assessed at diagnosis and for up to 20 years following diagnosis.

RESULTS

At diagnosis, 70% of patients had inflammatory disease, 9% stricturing, and 21% penetrating. Early age at diagnosis was associated with ileocolonic and upper GI disease (p = 0.015), and positive anti-Saccharomyces cerevisiae antibody (ASCA) was associated with ileal involvement (p = 0.008). Smoking was relatively protective against colonic, rather than ileal involvement at diagnosis (p < 0.02). At 20 years, 92% had progressed to a more severe disease type. Patients who progress to a more severe disease type require more frequent surgery (p < 0.00001). Multivariate analysis found disease progression to be associated with ileal disease location (p = 0.001) and positive ASCA (p = 0.003). Variant NOD2/CARD15 alleles were protective against rapid progression of disease phenotype (p = 0.04). The presence of perianal disease was independent of intestinal penetrating disease.

CONCLUSIONS

The progression of disease type in CD is associated with the need for more frequent surgery. Rapid progression is associated with ileal disease and positive ASCA, and delayed progression is associated with variant NOD2/CARD15 alleles. Consideration should be given to a separate Vienna classification for perianal disease.

Crohn's is not a 6-week disease: lifelong management of mild to moderate Crohn's disease

Crohn's disease is an idiopathic, chronic inflammatory disorder of the digestive tract with heterogeneous clinical presentations. Crohn's is currently not a curable disease, and patients are faced with a lifetime of recurrent disease flare-ups and remissions. Management strategies for Crohn's must therefore be targeted toward lifelong management, taking into consideration not only the short-term but also the long-term aspects of the disease. With this in mind, here we review the classifications and natural history of Crohn's disease and discuss possible predictive factors for the disease evolution in a patient. Here we also evaluate the current preferable treatment practices, based on scientifically valid research and collective clinical experience, for the management of mild to moderate Crohn's disease.

The contribution of HLA genes to IBD susceptibility and phenotype

The human leukocyte antigen (HLA) region located on chromosome 6p encodes the highly polymorphic, classical class I and II genes essential for normal lymphocyte function; it also encodes a further 224 genes. Many early studies investigating this region were limited by small sample size, poor statistical methodology, population stratification and variable disease definition. Although more recent studies have improved study design, investigators are still challenged by the complex patterns of linkage disequilibrium across this gene-dense region, and by the disease heterogeneity characteristic of all genetically complex disorders. However, a number of important observations have emerged from recent studies: (1) the HLA harbours gene(s) that determine susceptibility to colonic inflammation in both ulcerative colitis (UC) and Crohn's disease (CD); (2) most of the specific associations with UC and CD appear to differ; (3) associations between different ethnic groups differ; (4) markers in the HLA might predict the course of disease and the development of complications, notably the extraintestinal manifestations of disease.

Clinical characteristics of familial versus sporadic Crohn's disease using the Vienna Classification

BACKGROUND

The etiology of Crohn's disease, an illness protean in its manifestations, may be better resolved through studies involving more homogenous subgroups of patients. Because a strong genetic influence exists, family history of inflammatory bowel disease may be a useful variable for patient classification if patients with familial and sporadic Crohn's disease are clinically different. Our study attempted to define any possible differences.

METHODS

The medical records of 552 patients were reviewed, and patients were classified according to guidelines of the Vienna Classification. Patients were then divided based on family history of inflammatory bowel disease, and the familial and sporadic groups were compared.

RESULTS

Overall, 422 (78.9%) patients were diagnosed before age 40 years (A1) and 114 (21.1%) at age 40 years or older (A2). There were 141 (26.3%) patients with disease involving the terminal ileum only (L1), 211 (39.4%) in the colon only (L2), 117 (21.9%) in the terminal ileum and colon (L3), and 66 (12.3%) in the upper gastrointestinal tract (L4). Disease behavior, as determined at the time of last visit or telephone contact, was nonstricturing, nonpenetrating (B1) in 149 (27.9%) patients, stricturing (B2) in 50 (9.3%) patients, and penetrating (B3) in 336 (62.8%) patients. Comparisons among the groups of 53 patients with first-degree relatives only, the 96 patients with either first-, second-, or third-degree relatives (familial CD group), and the 439 patients with sporadic disease demonstrated no differences in sex, age at diagnosis, or disease location. There was a difference in disease behavior between the familial and sporadic groups (p = 0.048) that failed to exist when nonstricturing, nonpenetrating cases were excluded. No such difference was observed between the first-degree relatives only group and the sporadic group (p > 0.10).

CONCLUSIONS

Using the Vienna Classification, familial and sporadic Crohn's disease differed only in disease behavior. However, this difference failed to exist after patients with nonstricturing, nonpenetrating disease were excluded. Therefore, familial and sporadic groups appear to be quite similar clinically, and family history does not appear to be a variable useful for disease subclassification.

Clinical relevance of advances in genetics and pharmacogenetics of IBD

Crohn's disease and ulcerative colitis result from an inappropriate response of the mucosal immune system to the normal enteric flora in a genetically susceptible individual. During the past decade, exciting progress has been made in our understanding of the contribution of genetics to inflammatory bowel disease susceptibility and phenotype. This article reviews recent advances in the genetics of inflammatory bowel disease and explores how they might impact on clinical practice. Current knowledge of the genetic basis for disease susceptibility, phenotype, and response to therapy is explored and the factors currently limiting the translation of this knowledge to clinical practice is discussed.

Is it time to re-classify Crohn's disease?

From the original anatomic classification of Crohn's disease in 1975, there have been three subsequent published classifications. The most recent, the Vienna Classification arose from a 1998 World Congress of Gastroenterology Working Party that attempted to prospectively design a simple and objective Crohn's disease phenotypic classification that encompassed components of age at onset, anatomic location and disease behavior. Subsequent application of the Vienna Classification to clinical practice has demonstrated that the Crohn's disease phenotype changes markedly over time, with nearly 80% of inflammatory disease ultimately evolving into a stricturing or penetrating pattern of behavior, and 15% undergoing a change in anatomic location. Furthermore, in controlled studies, the ability of inflammatory bowel disease experts to similarly identify the disease phenotypes, using the Vienna classification, ranges from poor to fair. Taken together, these failings markedly limit the utilization of the Vienna classification of Crohn's disease in clinical trails or disease management. Recent advances in determining the genetic linkages associated with Crohn's disease will undoubtedly lead to a revised Crohn's disease classification that will combine genotype with phenotype. Nevertheless, before this new classification can become a reality we will need to reconcile a number of key elements, including; (1) localization and grouping of all inflammatory bowel disease(IBD) gene mutations, (2) discovering the function of the IBD genes, (3) understanding the impact of the environment on phenotypic expression, and, (4) linking to well-defined phenotypic databases that will permit accurate prediction of disease natural history and therapeutic response. Indeed, the consistency of the phenotypic data available may be the greatest single challenge in unraveling the complexities of inflammatory bowel disease and developing a new classification of Crohn's disease.

Natural history and clinical behavior of Crohn's disease extending beyond two decades

Crohn's disease is a heterogeneous inflammatory disorder characterized by strictures or perforating complications. Information on natural history is limited. In the present study, 150 patients with long-standing Crohn's disease, including 81 females and 69 males, were seen continuously by a single clinician for at least 20 years. Additional retrospective data were available extending for >40 years and 13 have now died, usually with an advanced malignancy. To evaluate disease expression, phenotypic clinical characteristics defined by the 1998 Vienna classification for Crohn's disease were used and included age at diagnosis, location of disease, and disease behavior at the time of diagnosis or 10 years or 20 years after diagnosis. Most patients were initially diagnosed before the age of 40 years (94%) and had ileocolonic disease (65.3%). At diagnosis, both females and males were most often classified with inflammatory disease (nonstenosing, nonpenetrating); however, over the course of the disease, particularly in the first decade, decreased numbers of patients with inflammatory disease and increased numbers with penetrating disease were seen. In addition, some with stenosing disease eventually developed penetrating disease. Disease localized to ileum alone was most often complicated by stricture formation, whereas ileocolonic disease was usually complicated by a penetrating complication. This shift in disease behavior indicates that Crohn's disease is a dynamic process that phenotypically evolves and progresses with time.

Treatment of Crohn's Disease of Inflammatory, Stenotic, and Fistulizing Phenotypes

The heterogeneous nature of Crohn's disease (CD) is reflected in the diversity of treatment options available for individual patients. The stratification of CD patients into more homogeneous groups based on disease location and disease behavior may provide clinicians with a more focused approach to therapeutic decision-making. Uncomplicated disease behaviors are typically treated medically. When complications arise and patterns of disease become more aggressive, combined medical and surgical approaches are often necessary and yield favorable results. The surgical management of CD can be as complex as the disease itself, and should involve a surgeon who professes a special expertise in inflammatory bowel disease. Progress in our understanding of the role of the interaction between the environment and the immune system in disease development has led to major advancements in the area of CD therapeutics. Current therapies target the various elements of the inflammatory cascade implicated in the pathogenesis of CD. The anti-inflammatory properties of the pharmacologic therapies presented in this review vary from actions that are extremely broad to those that are cellular or cytokine specific. Maximizing the efficacy of CD-directed therapies while minimizing their toxicity remains the principal objective in developing management strategies for CD patients. Maintaining good quality of life and maximizing adherence to therapies are also important considerations. Despite the various therapeutic options available for CD patients, chosen therapies should be based on the overall treatment goal for individual patients. Therapeutics can be broadly categorized as induction therapies (goal to treat active disease) and maintenance therapies (goal to prevent relapse of disease).