De Novo Colitis Associated With Rituximab in 21 Patients at a Tertiary Center

Obinutuzumab-Induced Inflammatory Bowel Disease-Like Pancolitis: A First Case Report

Introduction

Obinutuzumab is a type II anti-CD20 monoclonal antibody associated with a higher rate of toxicity when compared to rituximab. Gastrointestinal side-effects have been reported but data is still sparse.

Case Presentation

A 47-year-old female with medical history of stage IV follicular non-Hodgkin lymphoma under chemotherapy presented with chronic bloody diarrhea and iron deficiency anemia. Endoscopic and histologic features resembled inflammatory bowel disease (IBD), imposing a thorough differential diagnosis. The diagnosis of obinutuzumab-induced pancolitis was made and the drug was suspended with subsequent clinical improvement.

Conclusion

This is the first case report of obinutuzumab-induced pancolitis. The challenging differential diagnosis of IBD required a multidisciplinary approach with subsequent outcome and management implications.

Successful Treatment of Rituximab-Induced Crohn's Disease With Ustekinumab

Autoimmune optic papillitis is a rare disorder that causes progressive visual loss, often treated with rituximab (RTX). However, its use is not without risks. Here, we present a 51-year-old man who experienced vision loss because of autoimmune optic papillitis, which was well-controlled with RTX. Four years later, the patient developed abdominal pain and diarrhea and was found to have RTX-induced Crohn's disease (CD). The patient failed treatment with azathioprine, but was subsequently able to achieve clinical and endoscopic remission of his CD with ustekinumab, while continuing RTX therapy for autoimmune optic papillitis. This case report describes the efficacy of the anti-interleukin 12/23 monoclonal antibody in inducing remission of RTX-induced CD.

Key characteristics of anti-CD20 monoclonal antibodies and clinical implications for multiple sclerosis treatment

The recent success of anti-CD20 monoclonal antibody therapies in the treatment of multiple sclerosis (MS) has highlighted the role of B cells in the pathogenesis of MS. In people with MS, the inflammatory characteristics of B-cell activity are elevated, leading to increased pro-inflammatory cytokine release, diminished anti-inflammatory cytokine production and an accumulation of pathogenic B cells in the cerebrospinal fluid. Rituximab, ocrelizumab, ofatumumab, ublituximab and BCD-132 are anti-CD20 therapies that are either undergoing clinical development, or have been approved, for the treatment of MS. Despite CD20 being a common target for these therapies, differences have been reported in their mechanistic, pharmacological and clinical characteristics, which may have substantial clinical implications. This narrative review explores key characteristics of these therapies. By using clinical trial data and real-world evidence, we discuss their mechanisms of action, routes of administration, efficacy (in relation to B-cell kinetics), safety, tolerability and convenience of use. Clinicians, alongside patients and their families, should consider the aspects discussed in this review as part of shared decision-making discussions to improve outcomes and health-related quality of life for people living with MS.

Histologic manifestations of ocrelizumab-associated intestinal and hepatic injury in patients with multiple sclerosis

AIMS

Ocrelizumab is a humanized anti-CD20-monoclonal antibody that has recently been approved for the treatment of certain types of multiple sclerosis. Isolated case reports of ocrelizumab-associated colitis have been reported in the literature. We present a case series of ocrelizumab-associated intestinal injury with a focus on histopathologic features and report a case of ocrelizumab-associated hepatitis.

METHODS AND RESULTS

A retrospective computerized search was conducted from 03/2017 to 08/2022, which identified six patients with suspected or clinically confirmed ocrelizumab-associated intestinal injury and one patient with hepatic injury. Pertinent clinical, endoscopic, and histopathologic findings were reviewed and recorded. Seven patients (six female, one male) were identified with ages ranging from 24 to 68 years. The presenting symptoms included diarrhoea (n = 5), abdominal pain (n = 3), hematochezia (n = 2), and vomiting (n = 1), nausea (n = 1) fever (n = 1), and weight loss (n = 1). Endoscopic findings ranged from normal (n = 1) to patchy colonic inflammation with or without ulceration (n = 4) and decreased mucosal vascular pattern in the rectum (n = 1). Crohn's disease was clinically suspected in two patients and ulcerative colitis in one patient. None of the patients had a prior confirmed diagnosis of inflammatory bowel disease. Histologic patterns of initial colonic injury included acute colitis/proctitis (n = 5), and chronic active colitis (n = 1). Follow-up ranged from 1 to 3 years and 10 months. All patients were alive at follow-up. Follow-up biopsies were available for four patients and findings included focal acute colitis (n = 1), apoptotic colopathy (n = 1) lymphocytic colitis (n = 1), and normal mucosa (n = 1). Four patients were treated with steroids and ocrelizumab was discontinued in three patients. Two patients were symptomatically managed with subsequent resolution of symptoms. The liver biopsy from the patient with a marked hepatic pattern of liver enzyme elevation showed an acute hepatitis pattern of injury with prominent centrilobular necrosis, which resolved upon discontinuation of the drug and treatment with steroids and azathioprine.

CONCLUSIONS

The histologic manifestations of ocrelizumab-associated intestinal injury are variable and can mimic inflammatory bowel disease. Hepatic injury can rarely manifest as an acute hepatitis pattern of injury with necrosis. Identifying ocrelizumab-associated injury is paramount in determining management, which often includes discontinuation of ocrelizumab therapy, and/or administration of immunosuppressive therapy.

Repurposing of rituximab biosimilars to treat B cell mediated autoimmune diseases

Rituximab, the first monoclonal antibody approved for the treatment of lymphoma, eventually became one of the most popular and versatile drugs ever in terms of clinical application and revenue. Since its patent expiration, and consequently, the loss of exclusivity of the original biologic, its repurposing as an off-label drug has increased dramatically, propelled by the development and commercialization of its many biosimilars. Currently, rituximab is prescribed worldwide to treat a vast range of autoimmune diseases mediated by B cells. Here, we present a comprehensive overview of rituximab repurposing in 115 autoimmune diseases across 17 medical specialties, sourced from over 1530 publications. Our work highlights the extent of its off-label use and clinical benefits, underlining the success of rituximab repurposing for both common and orphan immune-related diseases. We discuss the scientific mechanism associated with its clinical efficacy and provide additional indications for which rituximab could be investigated. Our study presents rituximab as a flagship example of drug repurposing owing to its central role in targeting cluster of differentiate 20 positive (CD20) B cells in 115 autoimmune diseases.

Infliximab rescue therapy in a case of severe granulomatous colitis associated with rituximab use

Colitis occurs in about 4% of individuals treated with rituximab. Optimal management of rituximab-induced colitis, which does not improve with cessation of the drug and supportive care alone, is poorly defined due to limited evidence. Severe refractory disease can lead to colectomy. We present a case of suspected rituximab-induced colitis occurring in a woman in her 70s suffering from rheumatoid arthritis. The patient achieved full clinical, endoscopic and histological remission of colitis with infliximab therapy. The use of biological therapy to treat rituximab-induced colitis can be a potentially organ-saving rescue therapy; however, it must be balanced against the increased risks of immunosuppression in patients already exposed to rituximab. While more evidence is required to fully understand the efficacy and risks of antitumour necrosis factor therapy in this scenario, our case provides an example of the successful use of infliximab for rituximab-induced colitis, which likely helped the patient avoid a colectomy.

Machine learning-based B cell-related diagnostic biomarker signature and molecular subtypes characteristic of ulcerative colitis

As an inflammatory bowel disease, ulcerative colitis (UC) does not respond well to current treatments. It is of positive clinical significance to further study the pathogenesis of UC and find new therapeutic targets. B lymphocytes play an important role in the pathogenesis of UC. The effect of anti-CD20 therapy on UC also provides new evidence for the involvement of B cells in UC process additionally, suggesting the important role and potential therapeutic value of B cells in UC. In this study, we screened the most critical immune cell-related gene modules associated with UC and found that activated B cells were closely related to the gene modules. Subsequently, key activated B cell-associated gene (BRG) signatures were obtained based on WGCNA and differential expression analysis, and three overlapping BRG-associated genes were obtained by RF and LASSO algorithms as BRG-related diagnostic biomarkers for UC. Nomogram model was further performed to evaluate the diagnostic ability of BRG-related diagnostic biomarkers, subsequently followed by UC molecular subsets identification and immunoinfiltration analysis. We also further verified the expressions of the three screened BRGs in vitro by using an LPS-induced NCM460 cell line model. Our results provide new evidence and potential intervention targets for the role of B cells in UC from a new perspective.

B cell-mediated CD4 T-cell costimulation via CD86 exacerbates pro-inflammatory cytokine production during autoimmune intestinal inflammation

Dysregulated B cell responses have been described in inflammatory bowel disease (IBD) patients; however, the role of B cells in IBD pathology remained incompletely understood. We here provide evidence for the detrimental role of activated B cells during the onset of autoimmune intestinal inflammation. Using Wiskott-Aldrich Syndrome interacting protein deficient (Wipf1-/-) mice as a mouse model of chronic colitis, we identified clusters of differentiation (CD)86 expression on activated B cells as a crucial factor exacerbating pro-inflammatory cytokine production of intestinal CD4 T cells. Depleting B cells through anti-CD20 antibody treatment or blocking costimulatory signals mediated by CD86 through cytotoxic T lymphocyte antigen-4-immunoglobulin (CTLA-4-Ig) diminished intestinal inflammation in our mouse model of chronic IBD at the onset of disease. This was due to a reduction in aberrant humoral immune responses and reduced CD4 T cell pro-inflammatory cytokine production, especially interferon-g (IFN-g) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interestingly, in addition to B cells isolated from the inflamed colon of Wipf1-/- mice, we also found CD86 mRNA and protein expression upregulated on activated B cells isolated from inflamed tissue of human patients with IBD. B cell activation and CD86 expression were boosted by soluble CD40L in vitro, which we found in the serum of mice and human patients with IBD. In summary, our data provides detailed insight into the contribution of B cells to intestinal inflammation, with implications for the treatment of IBD.

Role of B Cells in Relapsing-Remitting and Progressive Multiple Sclerosis and Long-Term Effects of B Cell Depletion

Depletion of circulating B lymphocytes using anti-CD20 monoclonal antibodies (mAbs) greatly reduces inflammatory activity in relapsing multiple sclerosis (RMS); it reduces progression to a lesser extent in nonrelapsing progressive MS. Mechanisms whereby anti-CD20 mAbs reduce MRI and clinical relapse activity in people with RMS are still being elucidated. Anti-CD20 agents do not fully protect from nonrelapsing disease progression, possibly due to their inability to cross the blood-brain barrier and inability to ameliorate the full extent of biology of MS progression. Anti-CD20 mAbs have a relatively favorable safety profile, at least in the short-term. Long-term safety studies are still needed.

Cytokine Release Syndrome-Associated Colitis: Insights From a Case of Rituximab-Induced Pancolitis

Rituximab (RTX), a widely used monoclonal antibody for hematologic malignancies and rheumatologic disorders, is known for infusion-related reactions. However, its potential to induce colitis is often overlooked. We present an 85-year-old woman with chronic lymphocytic leukemia experiencing severe adverse effects during her fourth RTX infusion, including abdominal pain, hypotension, and bright red blood per rectum. Computed tomography of the abdomen and pelvis with contrast revealed pancolonic mural wall thickening without perforation. Prompt treatment with vasopressors and intravenous fluids led to symptom resolution within 24 hours. We highlighted the importance of recognizing RTX-induced colitis and discussed and depicted immunological dysregulation mechanisms involved.

Ocrelizumab-induced colitis and cytomegalovirus infection and their disadvantageous interaction with underlying multiple sclerosis

Ocrelizumab is a humanized monoclonal antibody against the B-lymphocyte antigen CD20 and the only approved treatment option in primary progressive multiple sclerosis. Herpesvirus-related infections like cytomegalovirus (CMV) infections are common in patients receiving ocrelizumab, whereas gastrointestinal side effects with inflammatory bowel disease (IBD) like esophagitis or colitis are very rare. This case report describes the challenging clinical, endoscopic, and histologic features of an ocrelizumab-induced colitis overlapping with CMV infection and their disadvantageous interaction with the underlying multiple sclerosis.

Ulcerative colitis induced by obinutuzumab in a patient treated for a folicular lymphoma

An increasing use of immunomodulatory drugs has led to a corresponding increase in treatment-related pathologies such as inflammatory bowel disease. Here, we present a case of ulcerative colitis due to Obinutuzumab, an antiCD20 monoclonal approved for the treatment of Non-Hodgkin lymphomas.

Persistent Apoptotic Enteropathy in an Individual With Marginal Cell Lymphoma

Apoptotic enteropathy is a histological finding of increased crypt apoptosis that is commonly associated with diarrhea. Several etiologies for this disease state including immunodeficiency, autoimmune, infection, hereditary, checkpoint inhibitors, immunosuppressants, and immunomodulators have been previously described. We describe an extremely rare case of a patient with marginal cell lymphoma treated with bendamustine, rituximab, and obinutuzumab presenting with severe, relapsing, chronic diarrhea with persistent apoptotic enteropathy of unknown etiology, despite hematological remission and discontinuation of treatment for 1 year.

Anti-CD20 monoclonal antibody (mAb) therapy and colitis: A case series and review

The US Food and Drug Administration (FDA) recently issued a warning regarding ocrelizumab due to reports of colitis among patients taking this medication. Since it is the only FDA-approved therapy for primary progressive multiple sclerosis (PPMS), further research on this adverse event is necessary, and healthcare professionals should be informed of potential treatment options. In this review, we summarize the available data on the incidence of inflammatory colitis associated with anti-CD20 monoclonal antibodies (mAbs), such as ocrelizumab and rituximab, used in MS treatment. Although the exact pathophysiology of anti-CD20-induced colitis remains unknown, immunological dysregulation through treatment-mediated B-cell depletion has been proposed as a possible mechanism. Our study highlights the importance of clinicians being aware of this potential side effect, and patients taking these medications should be closely monitored for any new-onset gastrointestinal symptoms or diarrheal illness. Research indicates that prompt intervention with endoscopic examination and medical or surgical therapies can ensure timely and effective management, thus improving patient outcomes. However, large-scale studies are still needed to determine the associated risk factors and to establish definitive guidelines for the clinical evaluation of MS patients on anti-CD20 medications.

Predominant Antibody Deficiency and Risk of Microscopic Colitis: a Nationwide Case-Control Study in Sweden

PURPOSE : Predominant antibody deficiency (PAD) disorders, including common variable immunodeficiency (CVID), have been linked to increased risk of gastrointestinal infections and inflammatory bowel diseases. However, there are limited data on the relationship between PAD, specifically CVID, and risk of microscopic colitis (MC).

METHODS

We performed a nationwide case-control study of Swedish adults with MC diagnosed between 1997 and 2017 (n = 13,651). Data on biopsy-verified MC were retrieved from all of Sweden's pathology departments through the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) study. We defined predominant antibody deficiency using International Union of Immunologic Societies (IUIS) phenotypic classification. Individuals with MC were matched to population controls by age, sex, calendar year, and county. We used logistic regression to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

The prevalence of PAD in MC was 0.4% as compared to 0.05% in controls. After adjustment for potential confounders, this corresponded to an aOR of 7.29 (95%CI 4.64-11.63). The magnitude of the association was higher for CVID (aOR 21.01, 95% 5.48-137.44) compared to other antibody deficiencies (aOR 6.16, 95% CI 3.79-10.14). In exploratory analyses, the association between PAD and MC was particularly strong among males (aOR 31.73, 95% CI 10.82-135.04).

CONCLUSION

In this population-based study, predominant antibody deficiency was associated with increased risk of MC, particularly among males. Clinicians who encounter these patients should consider a detailed infectious history and screening for antibody deficiency.

Rituximab-Induced Colitis and Esophagitis in a Patient With Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis (GPA) is a small vessel vasculitis that affects many organ systems with varying disease severity. GPA commonly affects the sinuses and lung parenchyma. However, GPA can affect the gastrointestinal tract and may present as colitis. Immunosuppressive therapy, like rituximab (RTX), is used for the management of this disease. Rituximab is generally well-tolerated but has rare side effects that have been shown to mimic colitis in inflammatory diseases. Our case is a 44-year-old female with a history of GPA who presented with dysphagia, abdominal pain, and diarrhea. The patient received a maintenance dose of RTX six months before the presentation. The patient was seronegative for anti-neutrophilic cytoplasmic antibodies against proteinase 3 (PR3 ANCA). Infectious etiology was ruled out. Esophagogastroduodenoscopy (EGD) and colonoscopy showed esophageal bleeding ulcers and diffuse colonic inflammation, respectively. Pathology was consistent with esophagitis and colitis. Colonic mucosal biopsy failed to show evidence of vasculitis. The patient was treated with sucralfate and intravenous pantoprazole with an improvement in the symptoms. The repeat endoscopy on an outpatient basis showed the patient had full mucosal healing, including histological healing. Our patient likely had rituximab-induced colitis and esophagitis.

Refractory fulminant colitis following ocrelizumab therapy requiring colectomy in a patient with multiple sclerosis

A woman in her 40s was referred for acute and chronic postprandial abdominal cramps on a background of relapsing remitting multiple sclerosis on ocrelizumab therapy as well as coeliac disease on a gluten-free diet, with a family history of ulcerative colitis. Initial colonoscopy demonstrated mild patchy colitis. The patient was trialled on mesalazine, which was ceased due to intolerance. Subsequently, she continued on mercaptopurine monotherapy for management of mild symptoms. Despite this, her symptoms rapidly progressed, with endoscopic and histological evidence of severe rectal-sparing pancolonic inflammation, consistent with severe ocrelizumab-induced colitis. This was refractory to intravenous methylprednisolone and intravenous cyclosporine rescue therapy, requiring surgical management with a subtotal colectomy and subsequent ileorectal anastomosis, after which she remained in clinical, endoscopic and histological remission.

B cell expansion hinders the stroma-epithelium regenerative cross talk during mucosal healing

Therapeutic promotion of intestinal regeneration holds great promise, but defining the cellular mechanisms that influence tissue regeneration remains an unmet challenge. To gain insight into the process of mucosal healing, we longitudinally examined the immune cell composition during intestinal damage and regeneration. B cells were the dominant cell type in the healing colon, and single-cell RNA sequencing (scRNA-seq) revealed expansion of an IFN-induced B cell subset during experimental mucosal healing that predominantly located in damaged areas and associated with colitis severity. B cell depletion accelerated recovery upon injury, decreased epithelial ulceration, and enhanced gene expression programs associated with tissue remodeling. scRNA-seq from the epithelial and stromal compartments combined with spatial transcriptomics and multiplex immunostaining showed that B cells decreased interactions between stromal and epithelial cells during mucosal healing. Activated B cells disrupted the epithelial-stromal cross talk required for organoid survival. Thus, B cell expansion during injury impairs epithelial-stromal cell interactions required for mucosal healing, with implications for the treatment of IBD.

Crohn's disease induced by ocrelizumab in a patient with multiple sclerosis

Drug-induced inflammatory bowel disease (IBD) is a clinical entity on the rise due to the frequent use of immunomodulatory therapy. Here we report the case of Crohn's disease due to Ocrelizumab, a humanized anti-CD20 monoclonal antibody approved for the treatment of multiple sclerosis. The exact mechanism by which anti-CD20 antibodies can trigger IBD is unknown, but since IBD and multiple sclerosis are processes included within the spectrum of immunomediated diseases, we could suggest that Ocrelizumab could trigger IBD in genetically predisposed patients.

Dual biologic therapy with ocrelizumab for multiple sclerosis and vedolizumab for Crohn’s disease: A case report and review of literature

BACKGROUND

Little is known about the safety and efficacy of using two or more biologics for the treatment of immune-mediated diseases, including Crohn’s disease (CD).

CASE SUMMARY

This case report and narrative review demonstrate the potential safety of dual biologic therapy (DBT) in a 45-year-old female with two separate immune-mediated diseases. She had a history of multiple sclerosis for which she was receiving treatment with ocrelizumab, and she had been recently diagnosed with CD after presenting with diarrhoea. The CD diagnosis was confirmed radiologically, endoscopically, histologically, and biochemically. The patient received treatment with vedolizumab, a gut-specific inhibitor of the α₄β₇ integrin on leukocytes. No adverse reactions were observed for the duration of treatment. The safety of ocrelizumab and vedolizumab for the treatment of different immune-mediated diseases was demonstrated.

CONCLUSION

DBT may be a safe and effective option for the treatment of refractory disease or multiple immune-mediated diseases. Newer biologics, which have improved safety profiles and gut specificity, may provide promising avenues for treatment. However, caution must be exercised in the appropriate selection of biologics given their inherent immunosuppressive properties, side effects, and efficacy profiles. Current evidence suggests that biologic therapy is not associated with a worse prognosis in patients with coronavirus disease 2019, but treatment decisions should be made in a multidisciplinary setting. Further research from controlled trials is needed to better understand the safety profile of DBT in CD. The immunopathological mechanisms underlying DBT also remain to be clarified.

ECCO Topical Review on Clinicopathological Spectrum and Differential Diagnosis of Inflammatory Bowel Disease

INTRODUCTION

Many diseases can imitate inflammatory bowel disease [IBD] clinically and pathologically. This review outlines the differential diagnosis of IBD and discusses morphological pointers and ancillary techniques that assist with the distinction between IBD and its mimics.

METHODS

European Crohn's and Colitis Organisation [ECCO] Topical Reviews are the result of an expert consensus. For this review, ECCO announced an open call to its members and formed three working groups [WGs] to study clinical aspects, pathological considerations, and the value of ancillary techniques. All WGs performed a systematic literature search.

RESULTS

Each WG produced a draft text and drew up provisional Current Practice Position [CPP] statements that highlighted the most important conclusions. Discussions and a preliminary voting round took place, with subsequent revision of CPP statements and text and a further meeting to agree on final statements.

CONCLUSIONS

Clinicians and pathologists encounter a wide variety of mimics of IBD, including infection, drug-induced disease, vascular disorders, diverticular disease, diversion proctocolitis, radiation damage, and immune disorders. Reliable distinction requires a multidisciplinary approach.

Histologic Findings and Tissue B-Cell Depletion in Endoscopic Mucosal Biopsy Specimens of the Gastrointestinal Tract After Treatment With Rituximab

OBJECTIVES

Rituximab (RTX) is associated with variable adverse gastrointestinal (GI) events. However, the histologic correlate in affected patients is not well defined.

METHODS

Patients (n = 93) who had received RTX and undergone endoscopic biopsies were identified. CD20 and PAX5 immunostains were performed on biopsy specimens showing inflammatory pathology (group A, 36 patients) and 35 of 57 noninflammatory biopsies (group B) that were taken within 1 year from the last RTX infusion. Histologic findings were correlated with tissue B-cell depletion (CD20/PAX5-/-).

RESULTS

B cells were depleted in 12 (33%) of 36 group A biopsy specimens. After excluding biopsies taken more than 1 year from the last RTX infusion, the frequencies of tissue B-cell depletion were similar between group A (12/26; 46.2%) and group B (17/35; 48.6%) (P > .05). Also, the frequencies of inflammatory pathology were not statistically different whether B cells were depleted or not (P > .05). In group A with tissue B-cell depletion (n = 12), causality was indicated in two (17%) cases showing lymphocytic colitis pattern of injury (LCPI).

CONCLUSIONS

In RTX-treated patients, tissue B-cell depletion does not appear to be the main cause of inflammatory pathology in the GI tract. A minor subset, however, develops histologic evidence of potential RTX-induced effect, notably in the form of LCPI.

Product review on MAbs (alemtuzumab and ocrelizumab) for the treatment of multiple sclerosis

Traditionally, the management of active relapsing remitting MS was based on the, so-called, maintenance therapy, which is characterized by continuous treatment with particular disease modifying therapy (DMT), and a return of disease activity when the drug is discontinued. Another approach is characterized by a short treatment course of a DMT, which is hypothesized to act as an immune reconstitution therapy (IRT), with the potential to protect against relapses for years after a short course of treatment. Introduction of monoclonal antibodies in the treatment of MS has revolutionized MS treatment in the last decade. However, given the increasingly complex landscape of DMTs approved for MS, people with MS and neurologists are constantly faced with the question which DMT is the most appropriate for the given patient, a question we still do not have an answer to. In this product review, we will discuss the first DMT that acts as IRT, an anti-CD52 monoclonal antibody alemtuzumab and an anti CD20 monoclonal antibody, ocrelizumab that has the potential to act as an IRT, but is administered continuously. Special emphasis will be given on safety in the context of COVID-19 pandemics and vaccination strategies.

Histopathology of non-IBD colitis practical recommendations from pathologists of IG-IBD Group

Pathologists are often called upon to diagnose colitides that differ from the two main forms of inflammatory bowel disease (IBD). These non-IBD colitides include infectious colitis, microscopic colitis, ischemic colitis, eosinophilic colitis, autoimmune enterocolitis, segmental colitis associated with diverticulosis, drug-induced colitis, radiation colitis and diversion colitis. The diagnosis of these different disease entities relies on the histopathological examination of endoscopic biopsies of the gastrointestinal tract. This paper reviews the main histomorphological characteristics of the various Non-IBD colitides.

Histopathology of Non-IBD Colitis. A practical approach from the Italian Group for the study of the gastrointestinal tract (GIPAD)

Non-IBD colitides (NIBDC) are intestinal diseases clinically and endoscopically overlapping with Inflammatory Bowel Diseases (IBD), sometimes with a similar histological picture. NIBDC include entities such as infectious colitis, ischemic colitis, pseudomembranous colitis, eosinophilic colitis, autoimmune enterocolitis, segmental colitis associated with diverticulosis, drug-induced colitis, radiation-induced colitis, diversion colitis, and microscopic colitis, this last including two entities: collagenous and lymphocytic colitis. The knowledge of the most useful histological features and the main clinical data for each entity is mandatory in daily clinical practice, for correct pathological diagnosis and clinical management.

Ocrelizumab-induced inflammatory bowel disease-like illness characterized by esophagitis and colitis

Ocrelizumab is an intravenous anti-CD20 monoclonal antibody, approved for use in primary progressive multiple sclerosis due to its selective depletion of B-lymphocytes. Herein we describe the case of a 56-year-old female who developed odynophagia and bloody diarrhea following treatment with ocrelizumab. This was characterized endoscopically by ulcerations in the esophagus and colon. The patient was treated with high-dose intravenous glucocorticoids with good clinical response.

Diagnosis and Management of Autoimmune Hemolytic Anemia in Patients with Liver and Bowel Disorders

Anemia is a common feature of liver and bowel diseases. Although the main causes of anemia in these conditions are represented by gastrointestinal bleeding and iron deficiency, autoimmune hemolytic anemia should be considered in the differential diagnosis. Due to the epidemiological association, autoimmune hemolytic anemia should particularly be suspected in patients affected by inflammatory and autoimmune diseases, such as autoimmune or acute viral hepatitis, primary biliary cholangitis, and inflammatory bowel disease. In the presence of biochemical indices of hemolysis, the direct antiglobulin test can detect the presence of warm or cold reacting antibodies, allowing for a prompt treatment. Drug-induced, immune-mediated hemolytic anemia should be ruled out. On the other hand, the choice of treatment should consider possible adverse events related to the underlying conditions. Given the adverse impact of anemia on clinical outcomes, maintaining a high clinical suspicion to reach a prompt diagnosis is the key to establishing an adequate treatment.

Rituximab-induced Ileocolitis in a Patient with Gastric MALToma: A Case Report and Literature Review

Rituximab (RTX) is effective for treating cancer, but reports of RTX-associated enterocolitis are limited. We herein report the case of a 65-year-old man who developed RTX-induced ileocolitis. He was diagnosed with gastric mucosa-associated lymphoid tissue lymphoma (MALToma) and treated with RTX. He complained of bloody diarrhea after RTX. Mucosal inflammation on colonoscopy indicated RTX-induced ileocolitis. He was treated with corticosteroids, and his symptoms improved. We reviewed the RTX-associated gastrointestinal adverse events and classified the features into ulcerative colitis, Crohn's disease, microscopic colitis, and ileocolitis. To our knowledge, this is the first case of a Japanese patient who developed RTX-induced ileocolitis.

Crohn's Disease Following Rituximab Treatment for Follicular Lymphoma in a Patient with Synchronous Gastric Signet Ring Cells Carcinoma: A Case Report and Literature Review

Recently, there have been a few reports of rituximab (RTX)-induced Crohn's disease, but there is no literature available on successful long-term treatment and the clinical outcome of this condition. We retrospectively analyzed the clinical data of a rare case of Crohn's disease induced by RTX administered as induction and prolonged maintenance therapy of a follicular lymphoma, diagnosed synchronously with a gastric signet ring cells carcinoma, treated at our hospital.