Inflammatory Bowel Disease Extending Its Reach

Abstract

As medical students and residents, we learned about the classic extraintestinal manifestations of inflammatory bowel disease (IBD): ankylosing spondylitis, peripheral arthritis, uveitis, pyoderma gangrenosum, erythema nodosum, and primary sclerosing cholangitis. In recent years, we have seen an extensive amount of literature emerge on less familiar extraintestinal complications of ulcerative colitis (UC) and Crohn’s disease; most notably osteoporosis and, to a lesser extent, thromboembolism. Two articles in this month’s Gastroenterology remind us that the effects of IBD extend to every corner of the body, including the lung and the central nervous system.1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar, 2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar The 2 studies use roughly similar techniques—large databases, containing both patients with IBD and population controls, were searched for diagnoses of interest. A description of each database is necessary to understand the strengths and the limitations of these studies. During the past decade, Bernstein et al3Bernstein C.N. Blanchard J.F. Rawsthorne P. Wajda A. Epidemiology of Crohn’s disease and ulcerative colitis in a central Canadian province a population-based study.Am J Epidemiol. 1999; 149: 916-924Google Scholar have created a population-based cohort of patients with IBD from Manitoba, Canada, using an administrative provincial health database and a validated algorithm based on codes from the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). The algorithm was validated by medical record review of a sample of patients and resulted in greater than 90% accuracy for the diagnosis of IBD. These investigators have used this database and cohort to report on the descriptive epidemiology of Crohn’s disease and UC3Bernstein C.N. Blanchard J.F. Rawsthorne P. Wajda A. Epidemiology of Crohn’s disease and ulcerative colitis in a central Canadian province a population-based study.Am J Epidemiol. 1999; 149: 916-924Google Scholar; furthermore, they have contributed to the literature on a whole host of IBD-related outcomes, including the risk of classic extraintestinal manifestations,4Bernstein C.N. Blanchard J.F. Rawsthorne P. Yu N. The prevalence of extraintestinal diseases in inflammatory bowel disease a population-based study.Am J Gastroenterol. 2001; 96: 1116-1122Google Scholar cancer,5Bernstein C.N. Blanchard J.F. Kliewer E. Wajda A. Cancer risk in patients with inflammatory bowel disease a population-based study.Cancer. 2001; 91: 854-862Google Scholar bone fractures,6Bernstein C.N. Blanchard J.F. Leslie W. Wajda A. Yu B.N. The incidence of fracture among patients with inflammatory bowel disease. A population-based cohort study.Ann Intern Med. 2000; 133: 795-799Google Scholar and venous thromboembolism.7Bernstein C.N. Blanchard J.F. Houston D.S. Wajda A. The incidence of deep venous thrombosis and pulmonary embolism among patients with inflammatory bowel disease a population-based cohort study.Thromb Haemost. 2001; 85: 430-434Google Scholar The University of Manitoba IBD cohort has grown over time to include more than 8000 patients.1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar In the present study, the investigators searched their IBD database for ICD-9-CM codes for various immune-mediated diseases (eg, asthma, bronchitis, arthritis, thyroiditis, multiple sclerosis [MS], neuropathy, myasthenia gravis, chronic renal disease, psoriasis, and pericarditis) and calculated a period prevalence (1984 to 2003).1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar A control group consisting of 10 Manitobans matched to each of the IBD cases on age, sex, postal code, and date of IBD diagnosis was identified, and a period prevalence for immune-mediated diseases in this cohort was similarly calculated. The ratio of autoimmune disease prevalence in the 2 groups was then calculated.1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar Gupta et al2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar used the resources of the General Practice Research Database (GPRD) from the United Kingdom to investigate the association between IBD and immune-mediated neurological disorders such as MS, optic neuritis (ON), and unspecified demyelinating disorders. The GPRD contains computerized medical records of general practitioners whose case panels in total comprise 6% of the entire British population; therefore, it serves as a proxy for a population-based study. Diagnostic codes in the GPRD are based on the Oxford Medical Indexing System (OXMIS). The investigators had previously shown by medical record review that their algorithm for identifying IBD by using OXMIS codes was reasonably accurate.8Lewis J.D. Brensinger C. Bilker W.B. Strom B.L. Validity and completeness of the General Practice Research Database for studies of inflammatory bowel disease.Pharmacoepidemiol Drug Safety. 2002; 11: 211-218Google Scholar The investigators have used this very large cohort of patients with IBD (n > 20,000) to investigate the relative and absolute risk of non-Hodgkin lymphoma, to study the influence of antibiotics on the risk of exacerbations of IBD, and to determine if exacerbations of IBD followed seasonal patterns.9Lewis J.D. Bilker W.B. Brensinger C. Deren J.J. Vaughn D.J. Strom B.L. Inflammatory bowel disease is not associated with an increased risk of lymphoma.Gastroenterology. 2001; 121: 1080-1087Google Scholar, 10Lewis J.D. Aberra F.N. Lichtenstein G.R. Bilker W.B. Brensinger C. Strom B.L. Seasonal variation in flares of inflammatory bowel disease.Gastroenterology. 2004; 126: 665-673Google Scholar, 11Aberra F.N. Brensinger C.M. Bilker W.B. Lichtenstein G.R. Lewis J.D. Antibiotic use and the risk of flare of inflammatory bowel diseas.Clin Gastroenterol Hepatol. 2005; 3: 459-465Google Scholar Other investigators have used the GPRD to estimate mortality, fracture risk, and renal disease risk in patients with IBD.12Card T. Hubbard R. Logan R.F. Mortality in inflammatory bowel disease a population-based cohort study.Gastroenterology. 2003; 125: 1583-1590Google Scholar, 13Card T. West J. Hubbard R. Logan R.F. Hip fractures in patients with inflammatory bowel disease and their relationship to corticosteroid use a population based cohort study.Gut. 2004; 53: 251-255Google Scholar, 14Van Staa T.P. Travis S. Leufkens H.G. Logan R.F. 5-aminosalicylic acids and the risk of renal disease a large British epidemiologic study.Gastroenterology. 2004; 126: 1733-1739Google Scholar In the present study, they identified OXMIS codes for MS, demyelination, ON, and retrobulbar neuritis in both the IBD cohort and in a control cohort composed of 4 patients with GPRD matched to each of the IBD cases on year of birth, sex, and primary care practice.2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar (Other investigators have shown that OXMIS codes for MS are accurate.15Marrie R.A. Wolfson C. Sturkenboom M.C. et al.Multiple sclerosis and antecedent infections a case-control study.Neurology. 2000; 54: 2307-2310Google Scholar, 16Hernan M.A. Jick S.S. Olek M.J. Jick H. Recombinant hepatitis B vaccine and the risk of multiple sclerosis a prospective study.Neurology. 2004; 63: 838-842Google Scholar) The analysis was performed in 2 ways. The cross-sectional approach used an approach similar to Bernstein et al,1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar in which the prevalence of the diagnoses of interest (either before or after IBD diagnosis) in the IBD cohort was compared to the prevalence in the control cohort. The cohort analysis compared the incidence of neurologic diagnoses after a diagnosis of IBD in the IBD cohort with the incidence of these diagnoses in the control cohort.2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar What were the results? In the Manitoba study, the prevalence of immune-mediated disease in both the IBD cohort and the control cohort varied depending on the particular algorithm used to define the diagnosis of interest.1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar Because the investigators did not undertake a medical record review to validate coding algorithms for these conditions, they wisely chose to present a range of prevalences defined at the high end by the least specific algorithm (at least 1 health contact with appropriate ICD-9-CM code) and at the low end by the most specific (at least 5 health contacts with ICD-9-CM code). For example, the prevalence of asthma ranged from 8% to 21% in the UC cases, 7% to 20% in the Crohn’s disease cases, and 5% to 16% in the controls. Fortunately, the prevalence ratios did not change significantly in most cases. Thus, for UC, the prevalence ratio for asthma ranged from 1.5 to 1.7, and for Crohn’s disease, the ratio for asthma ranged from 1.3 to 1.4. In other words, patients with UC were 50%–70% more likely than population-based controls to have asthma, whereas patients with Crohn’s disease were 30%–40% more likely. Using the most rigorous algorithm, significant associations were observed between UC and the following conditions: asthma; bronchitis; arthritis; MS; and chronic renal disease, psoriasis, and pericarditis. For patients with Crohn’s disease, the prevalence of asthma, bronchitis, arthritis, psoriasis, and pericarditis were significantly higher than among controls. (MS was not significantly more prevalent among the Crohn’s disease cohort in this study.) Looking at the data in a different way, Manitobans with one of these immune-mediated conditions were more likely than those without to have been diagnosed with IBD, although minor differences in these associations were identified when stratified by IBD subtype or sex. In the GPRD study, the primary focus was on MS, ON, and demyelinating diseases.2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar The cross-sectional analysis suggested that patients with Crohn’s disease were 54% more likely than community controls to have been diagnosed with MS, ON, or other demyelinating condition and patients with UC were 75% more likely. Patients with IBD who were treated with azathioprine or 6-mercaptopurine seemed less likely to develop these conditions than those not treated. The association between IBD and MS, ON, and demyelination appeared to be stronger among patients with UC who smoked than among non-smokers, whereas smoking did not appear to significantly influence neurologic risk among the patients with Crohn’s disease. In the cohort analysis, patients with UC were between 2 and 3 times more likely than controls to be diagnosed later with MS, ON, or demyelination. Patients with Crohn’s disease were about twice as likely as controls to be diagnosed later with one of these conditions, but this did not quite meet statistical significance. What do the results mean, and why should we care? These studies are packed with so much information that space precludes detailed commentary, but a few points should be made. The results of both studies lend credence to the emerging concept that patients with 1 immune-mediated condition are more likely than the general population to have another autoimmune disease. Although this had been recognized for more classic autoimmune conditions, these studies provide more definitive proof that the association holds true for UC and Crohn’s disease, too. Many immune-mediated conditions are thought, like IBD, to be polygenic, and it is likely that some of these conditions share susceptibility genes, both in the major histocompatibility region of chromosome 6 and in non–major histocompatibility areas.17Becker K.G. Simon R.M. Bailey-Wilson J.E. et al.Clustering of non-major histocompatibility complex susceptibility candidate loci in human autoimmune diseases.Proc Natl Acad Sci U S A. 1998; 95: 9979-9984Google Scholar Secondly, the finding by Bernstein et al1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar of a significant association between IBD and pulmonary diseases such as asthma and bronchitis highlights an underappreciated extraintestinal manifestation—pulmonary involvement. The lung is clearly a target organ in IBD, especially UC. A wide variety of pulmonary conditions have been reported in IBD, and this topic has been recently reviewed.18Storch I. Sachar D. Katz S. Pulmonary manifestations of inflammatory bowel disease.Inflamm Bowel Dis. 2003; 9: 104-115Google Scholar Chronic bronchitis, bronchiectasis, bronchiolitis obliterans with organizing pneumonia, pulmonary vasculitis, and α-1 anti-trypsin deficiency have all been reported in association with UC. Pulmonary involvement with Crohn’s disease has been reported less commonly but ranges from colobronchial or esophagopulmonary fistula to tracheal involvement to bronchiolitis to granulomatous lung disease.19Casey M.B. Tazelaar H.D. Myers J.L. et al.Noninfectious lung pathology in patients with Crohn’s disease.Am J Surg Pathol. 2003; 27: 213-219Google Scholar Complicating the picture is the possibility of drug-induced lung disease—in the case of IBD, the most common offenders are mesalamine, sulfasalazine, and methotrexate. Pulmonary function testing in consecutive IBD patients yields abnormalities, usually diminution in forced expiratory volume or diffusing capacity, in approximately 50%.18Storch I. Sachar D. Katz S. Pulmonary manifestations of inflammatory bowel disease.Inflamm Bowel Dis. 2003; 9: 104-115Google Scholar Many of these patients are seemingly without pulmonary symptoms, leading many clinicians (this author included) to not actively press patients with IBD for respiratory symptoms. However, the long-term consequences of untreated pulmonary involvement in IBD may be substantial. At least 3 studies of cause-specific mortality in population-based IBD cohorts have identified an increased risk of death due to pulmonary diseases.20Ekbom A. Helmick C.G. Zack M. Holmberg L. Adami H.O. Survival and causes of death in patients with inflammatory bowel disease a population-based study.Gastroenterology. 1992; 103: 954-960Crossref Scopus (229) Google Scholar, 21Persson P.G. Bernell O. Leijonmarck C.E. Farahmand B.Y. Hellers G. Ahlbom A. Survival and cause-specific mortality in inflammatory bowel disease a population-based cohort study.Gastroenterology. 1996; 110: 1339-1345Google Scholar, 22Winther K.V. Jess T. Langholz E. Munkholm P. Binder V. Survival and cause-specific mortality in ulcerative colitis follow-up of a population-based cohort in Copenhagen County.Gastroenterology. 2003; 125: 1576-1582Google Scholar One might expect this risk to be elevated in patients with Crohn’s disease, because they are more likely to be cigarette smokers, and decreased in UC patients, who tend to be nonsmokers. However, the exact opposite is found—the deaths due to respiratory disease are elevated in UC, not Crohn’s, ranging from 50% to 87% higher than expected in the background population.20Ekbom A. Helmick C.G. Zack M. Holmberg L. Adami H.O. Survival and causes of death in patients with inflammatory bowel disease a population-based study.Gastroenterology. 1992; 103: 954-960Crossref Scopus (229) Google Scholar, 21Persson P.G. Bernell O. Leijonmarck C.E. Farahmand B.Y. Hellers G. Ahlbom A. Survival and cause-specific mortality in inflammatory bowel disease a population-based cohort study.Gastroenterology. 1996; 110: 1339-1345Google Scholar, 22Winther K.V. Jess T. Langholz E. Munkholm P. Binder V. Survival and cause-specific mortality in ulcerative colitis follow-up of a population-based cohort in Copenhagen County.Gastroenterology. 2003; 125: 1576-1582Google Scholar As Bernstein et al1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar point out in their conclusions, respiratory complaints in patients with IBD should be taken seriously, and probably should be investigated with pulmonary function testing at the very least. Finally, both studies detected an increased prevalence among IBD patients of immune-mediated neurologic disorders including MS, ON, and other demyelinating diseases.1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar, 2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar An association between IBD and MS has been investigated previously,23Rang E.H. Brooke B.N. Hermon-Taylor J. Association of ulcerative colitis with multiple sclerosis.Lancet. 1982; 2: 4Google Scholar, 24Kimura K. Hunter S.F. Thollander M.S. et al.Concurrence of inflammatory bowel disease and multiple sclerosis.Mayo Clin Proc. 2000; 75: 802-806Google Scholar but in these studies, the size of the cohorts investigated were not sufficiently large enough to produce robust results. One recent study of a referral-based cohort of patients with MS identified a higher-than-expected prevalence of IBD.25Edwards L.J. Constantinescu C.S. A prospective study of conditions associated with multiple sclerosis in a cohort of 658 consecutive outpatients attending a multiple sclerosis clinic.Multiple Sclerosis. 2004; 10: 575-581Google Scholar In both of the present studies, the association between IBD and MS appears stronger with UC than with Crohn’s disease.1Bernstein C.N. Wajda A. Blanchard J.F. The clustering of other chronic inflammatory diseases in inflammatory bowel disease a population-based study.Gastroenterology. 2005; 129: 827-836Abstract Full Text Full Text PDF Scopus (435) Google Scholar, 2Gupta G. Gelfand J.M. Lewis J.D. Increased risk of demyelinating diseases in patients with inflammatory bowel disease.Gastroenterology. 2005; 129: 819-826Abstract Full Text Full Text PDF Scopus (202) Google Scholar The mechanism behind this association remains unclear, but presumably is due in part to shared susceptibility genes.17Becker K.G. Simon R.M. Bailey-Wilson J.E. et al.Clustering of non-major histocompatibility complex susceptibility candidate loci in human autoimmune diseases.Proc Natl Acad Sci U S A. 1998; 95: 9979-9984Google Scholar The association between IBD and neurologic disorders remains underappreciated. Imaging studies of IBD patients without neurologic symptoms show white matter lesions in a substantial minority,26Geissler A. Andus T. Roth M. Focal white-matter lesions in brain of patients with inflammatory bowel disease.Lancet. 1995; 345: 897-898Google Scholar and peripheral neuropathies of various types have been described in conjunction with IBD.27Gondim F.A. Brannagan III, T.H. Sander H.W. Chin R.L. Latov N. Peripheral neuropathy in patients with inflammatory bowel disease.Brain. 2005; 128: 867-879Google Scholar In the latter case, there are reports of improvement with immunomodulatory therapy such as intravenous immunoglobulins.27Gondim F.A. Brannagan III, T.H. Sander H.W. Chin R.L. Latov N. Peripheral neuropathy in patients with inflammatory bowel disease.Brain. 2005; 128: 867-879Google Scholar Awareness of the link between IBD and MS, ON, and demyelination is all the more important in the era of infliximab and other biologic agents. First, a number of case reports and small case series have noted that blockade of tumor necrosis factor α with either etanercept or infliximab appeared to be associated with demyelinating disorders in patients with IBD or inflammatory arthritis.28Mohan N. Edwards E.T. Cupps T.R. et al.Demyelination occurring during anti-tumor necrosis factor alpha therapy for inflammatory arthritides.Arthritis Rheum. 2001; 44: 2862-2869Google Scholar, 29Foroozan R. Buono L.M. Sergott R.C. Savino P.J. Retrobulbar optic neuritis associated with infliximab.Arch Ophthalmol. 2002; 120: 985-987Google Scholar, 30Nanavati S.A. Ergun G.A. Schwartz J.T. Avoiding infliximab in the treatment of Crohn’s disease in patients with multiple sclerosis.Am J Gastroenterol. 2003; 98: 2333-2334Google Scholar, 31ten Tusscher M.P. Jacobs P.J. Busch M.J. de Graaf L. Diemont W.L. Bilateral anterior toxic optic neuropathy and the use of infliximab.BMJ. 2003; 326 (letter): 579Google Scholar, 32Mejico L.J. Infliximab-associated retrobulbar optic neuritis.Arch Ophthalmol. 2004; 122: 793-794Google Scholar, 33Strong B.Y. Erny B.C. Herzenberg H. Razzeca K.J. Retrobulbar optic neuritis associated with infliximab in a patient with Crohn disease.Ann Intern Med. 2004; 140 (letter): W34Google Scholar, 34Thomas Jr, C.W. Weinshenker B.G. Sandborn W.J. Demyelination during anti-tumor necrosis factor alpha therapy with infliximab for Crohn’s disease.Inflamm Bowel Dis. 2004; 10: 28-31Google Scholar Second, a randomized controlled trial of an anti–tumor necrosis factor α agent, lenercept, for treatment of MS reported a higher rate of MS exacerbations in the group receiving active drug.35The Lenercept Multiple Sclerosis Study Group and the University of British Columbia MS/MRI Analysis GroupTNF neutralization in MS results of a randomized, placebo-controlled multicenter study.Neurology. 1999; 53: 457-465Google Scholar For these reasons, the prescribing information for anti–tumor necrosis factor α therapies now contains warnings about the risk of demyelinating diseases in patients receiving these agents. These drugs are contraindicated in patients with known demyelinating disorders. Our sensitivity for detecting neurologic complications of biologic therapies should be heightened by recent events associated with natalizumab (Tysabri; Elan Corporation, PLC, Dublin, Ireland; and Biogen Idec, Cambridge, MA), a monoclonal antibody directed against α4 integrin, a type of adhesion molecule. This agent had been approved by the Food and Drug Administration for the treatment of MS in 2004, and a development program for the treatment of Crohn’s disease was well underway. In early 2005, the drug was withdrawn from the market after progressive multifocal leukoencephalopathy (PML) was reported in 2 patients with MS who had received natalizumab in clinical trials.36Kleinschmidt-DeMasters B.K. Tyler K.L. Progressive multifocal leukoencephalopathy complicating treatment with natalizumab and interferon beta-1a for multiple sclerosis.N Engl J Med. 2005; 353: 369-374Google Scholar, 37Langer-Gould A. Atlas S.W. Green A.J. Bollen A.W. Pelletier D. Progressive multifocal leukoencephalopathy in a patient treated with natalizumab.N Engl J Med. 2005; 353: 375-381Google Scholar Initially, some believed this catastrophic complication may have been caused by combination therapy with natalizumab and interferon β-1a (Avonex; Biogen Idec). However, Van Assche et al38Van Assche G. Van Ranst M. Sciot R. et al.Progressive multifocal leukoencephalopathy after natalizumab therapy for Crohn’s disease.N Engl J Med. 2005; 353: 362-368Google Scholar reinvestigated a patient with Crohn’s disease who had received natalizumab in a clinical trial and died in 2003 from what was thought to be an astrocytoma, and realized that the patient had actually died of PML. This patient had received multiple immunosuppressive agents in the past, but azathioprine had been discontinued 8 months before (and infliximab 20 months before) the development of neurologic symptoms. It is too early to fully understand the pathogenesis of PML in these patients. The disease typically occurs in profoundly immunosuppressed patients and is associated with reactivation of JC polyoma virus. Antibodies to this agent are found in the majority of adults. The virus causes an asymptomatic primary infection in childhood and remains latent in the kidneys and in lymphoid tissue. Presumably, inhibition of certain adhesion molecules led to reactivation of JC virus, and the increasing serum viral load after 3 infusions of natalizumab in the patient with Crohn’s disease reported by Van Assche et al38Van Assche G. Van Ranst M. Sciot R. et al.Progressive multifocal leukoencephalopathy after natalizumab therapy for Crohn’s disease.N Engl J Med. 2005; 353: 362-368Google Scholar would support this. The studies of the Manitoba and the GPRD IBD cohorts underline the propensity of our patients with IBD for developing autoimmune disorders affecting multiple organ systems. Recent events remind us that therapies may be associated with unexpected complications involving other organs. As gastroenterologists who wish to provide our patients with IBD the most comprehensive care, we need to remember our roots—we are all internists first and gastroenterologists second. Increased Risk for Demyelinating Diseases in Patients With Inflammatory Bowel DiseaseGastroenterologyVol. 129Issue 3PreviewBackground & Aims: Reports of multiple sclerosis (MS), demyelination, and optic neuritis (ON) associated with anti–tumor necrosis factor α therapy resulted in warnings on prescribing instructions for infliximab, etanercept, and adalimumab. However, the underlying relationship between IBD and these neurologic conditions has not been established. Methods: We performed a retrospective cohort study and a retrospective cross-sectional study using 1988 to 1997 data from the General Practice Research Database. Full-Text PDF The Clustering of Other Chronic Inflammatory Diseases in Inflammatory Bowel Disease: A Population-Based StudyGastroenterologyVol. 129Issue 3PreviewBackground & Aims: We aimed to discern the relative risk for several chronic inflammatory conditions in patients with ulcerative colitis (UC) and Crohn’s disease. Methods: We used the population-based University of Manitoba IBD Database that includes longitudinal files on all patients from all health system contacts identified by International Classification of Diseases, 9th revision, Clinical Modification codes for visit diagnosis. From the provincial database we extracted a control cohort matching the IBD patients 10:1 by age, sex, and geography. Full-Text PDF