La colite ulcérative : une conséquence exceptionnelle après traitement par rituximab

Therapeutic agents affecting the immune system and drug-induced inflammatory bowel disease (IBD): A review on etiological and pathogenetic aspects

In recent years, therapeutic agents affecting the immune system have been largely implemented in the treatment of various hematological, rheumatological and dermatological disorders. Their clinical use has offered important benefits for affected patients and has also ameliorated clinical outcome and prognosis in many cases. Nonetheless, as any treatment, the use of these drugs may be associated with side effects. One of the target organs in such cases is the gastrointestinal tract. In particular, the exacerbation or the onset of inflammatory bowel disease (IBD) in treated patients is not infrequent, although the mechanism of action of these agents may be different. In this review we will focus on the use of therapeutic agents affecting the immune system and the development or exacerbation of IBD, with a mention on the possible underlying pathogenetic mechanisms.

Lactobacillus reuteri Alleviates Gastrointestinal Toxicity of Rituximab by Regulating the Proinflammatory T Cells in vivo

Rituximab (RTX) is a widely used anticancer drug with gastrointestinal side effects, such as nausea, vomiting, and diarrhea. The reason for these side effects is still poorly understood. Previous studies have reported that the intestinal microbiota is associated with the occurrence of disease and the therapeutic effect of drugs. In this study, we observed mucosal damage, inflammatory cell infiltration and increased intestinal inflammatory factor expression in RTX-treated mice. RTX also changed the diversity of the intestinal microbiota in mice, and decreased abundance of Lactobacillus reuteri was observed in RTX-treated mice. Further experiments revealed that intragastric administration of L. reuteri in RTX-treated mice attenuated the intestinal inflammatory response induced by RTX and regulated the proportion of helper T (Th) cells. In conclusion, our data characterize the effect of the intestinal microbiota on RTX-induced intestinal inflammation, suggesting that modifying the gut microbiota may represent a positive strategy for managing adverse reactions.

Anti-Inflammatory Biologics and Anti-Tumoral Immune Therapies-Associated Colitis: A Focused Review of Literature

An increasing number of drugs including monoclonal antibodies and small molecules, either anti-inflammatory or immunity-enhancing, have been developed to treat human diseases and the number of medications in these classes is likely to expand in the future. The two most commonly used categories of such therapies are the anti-inflammatory group (anti- tumor necrosis factor (TNF) α, anti-interleukins/interleukin receptors, and anti-integrin bodies) and the anti-tumoral agents (immune checkpoint inhibitors, anti-CD20, and anti-endothelial growth factor). Although the anti-inflammatory biologics have brought about a revolutionary effect in the management of a variety of autoimmune disorders including rheumatologic diseases, inflammatory bowel disease, and inflammatory dermatological diseases, their ability to induce colitis in patients without a prior history of colitis or exacerbate quiescent colitis has been increasingly and unexpectedly recognized. While the use of immune-augmenting monoclonal antibody therapies results in a significant survival benefit in a subset of patients with malignancies, these monoclonal antibodies also have the ability to cause colitis through an apparent autoimmune mechanism. Colitis associated with these medications may demonstrate multiple histologic patterns including increased apoptosis (graft versus host disease (GVHD)-like), autoimmune enteropathy pattern, acute colitis pattern, ischemic colitis, inflammatory bowel disease pattern, either ulcerative colitis-like, Crohn’s disease-like, or fulminant colitis-like. In addition, anti-inflammatory biologics are known to cause or reactivate latent infections such as tuberculosis and increase the risk for malignancies including high-grade lymphomas as well as indolent lymphoproliferative disorders. Thus, the differential diagnosis for colitis in patients receiving therapeutic anti-inflammatory biologics or anti-tumoral agents can be broad. Optimal diagnosis and treatment requires a multidisciplinary approach. This review aims to provide an overview of the literature on the clinical features, histology, and treatment of these newly recognized anti-inflammatory biologic and anti-tumoral immune therapy-induced colitises and hopes this outlines will raise the vigilance of all clinicians of these entities.

A presentation of ulcerative colitis after rituximab therapy in a patient with multiple sclerosis and literature review

Multiple sclerosis (MS) is one of the most important demyelinating diseases that affects the central nervous system. Its treatment often involves a long-term disease modifying therapy. According to some studies, the prevalence of autoimmune disorders, such as autoimmune hepatitis (AIH) and ulcerative colitis (UC) is higher in MS patients than in the normal population. There are also few studies that have reported the onset of UC after rituximab therapy. The present study presents a report of a 31-years old female patient suffering from aggressive multiple sclerosis, which developed into autoimmune hepatitis during the MS therapy. Thereafter, she received rituximab for the treating both MS and AIH. One week after the third cycle of rituximab (6 doses of 1000 mg), she experienced abdominal pain, fever, and severe bloody diarrhea; finally, she was diagnosed with ulcerative colitis (UC). It seems that the administration of certain immunomodulators or immunosuppressive drugs may have a main role in the exacerbation of some autoimmune diseases.

Rituximab-induced Crohn's disease

The use of rituximab has significantly improved outcomes in patients with haematological malignancies and autoimmune disease. There are reports of rituximab-associated ulcerative colitis; however, we report for the first time, two cases of rituximab-induced Crohn's disease in elderly patients treated for lymphoma. Both patients had evidence of inflammation, ulceration, and granulomas consistent with Crohn's disease, and responded well to immunosuppression. The association of rituximab and ileocolitis suggests a protective effect of CD20 + lymphocytes in the gut, and implicates their depletion to the development and exacerbation of inflammatory bowel disease.

T regulatory cells and B cells cooperate to form a regulatory loop that maintains gut homeostasis and suppresses dextran sulfate sodium-induced colitis

Regulatory T cells (Tregs) and B cells present in gut-associated lymphoid tissues (GALT) are both implicated in the resolution of colitis. However, how the functions of these cells are coordinated remains elusive. We used the dextran sulfate sodium (DSS)-induced colitis model combined with gene-modified mice to monitor the progression of colitis, and simultaneously examine the number of Tregs and B cells, and the production of IgA antibodies. We found that DSS-treated mice exhibited more severe colitis in the absence of B cells, and that the adoptive transfer of B cells attenuated the disease. Moreover, the transfer of IL-10(-/-) B cells also attenuated colitis, suggesting that B cells inhibited colitis through an interleukin-10 (IL-10)-independent pathway. Furthermore, antibody depletion of Tregs resulted in exacerbated colitis. Intriguingly, the number of GALT Tregs in B cell-deficient mice was significantly decreased during colitis and the adoptive transfer of B cells into these mice restored the Treg numbers, indicating that B cells contribute to Treg homeostasis. We also found that B cells induced the proliferation of Tregs that in turn promoted B-cell differentiation into IgA-producing plasma cells. These results demonstrate that B cells and Tregs interact and cooperate to prevent excessive immune responses that can lead to colitis.

Regulatory B cells in human inflammatory and autoimmune diseases: from mouse models to clinical research

B cells have been generally considered to be positive regulators of immune responses because of their ability to produce antigen-specific antibodies and to activate T cells through antigen presentation. Impairment of B cell development and function may cause inflammatory and autoimmune diseases. Recently, specific B cell subsets that can negatively regulate immune responses have been described in mouse models of a wide variety of inflammatory and autoimmune diseases. The concept of those B cells, termed regulatory B cells, is now recognized as important in the murine immune system. Among several regulatory B cell subsets, IL-10-producing regulatory B cells are the most widely investigated. On the basis of discoveries from studies of such mice, human regulatory B cells that produce IL-10 in most cases are becoming an active area of research. There have been emerging data suggesting the importance of human regulatory B cells in various diseases. Revealing the immune regulation mechanisms of human regulatory B cells in human inflammatory and autoimmune diseases could lead to the development of novel B cell targeted therapies. This review highlights the current knowledge on regulatory B cells, mainly IL-10-producing regulatory B cells, in animal models of inflammatory and autoimmune diseases and in clinical research using human samples.

Regulatory B cells in mouse models of intestinal inflammation

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition with increasing incidence and prevalence around the world. Although B cells had generally been believed to play a pathogenic role in IBD due to the production of autoantibodies, a growing body of evidence from mouse models suggests the coexistence of pathogenic B cells and regulatory B cells, termed Breg, in this disorder. Since some unique techniques are required to closely study the Breg in gut-associated lymphoid tissues (GALT), we herein describe how to induce colitis in mice and how to analyze the phenotype and function of GALT-specific Breg.

Biologics-induced autoimmune diseases

PURPOSE OF REVIEW

Biological agents are therapies designed to target a specific molecular component of the immune system, and are currently licensed for use in autoimmune rheumatic, digestive, dermatological and systemic diseases. However, their use has been linked with the paradoxical development of autoimmune processes.

RECENT FINDINGS

More than 1500 cases of autoimmune diseases induced by biologics have been reported, including a wide variety of both systemic (lupus, vasculitis, sarcoidosis, antiphospholipid syndrome and inflammatory myopathies) and organ-specific (interstitial lung disease, uveitis, optic neuritis, peripheral neuropathies, multiple sclerosis, psoriasis, inflammatory bowel disease and autoimmune hepatitis) autoimmune processes. Although these processes are overwhelmingly associated with anti-TNF agents, recent cases have been associated with therapies directed against other cytokines, B or T-cells, illustrating that even though targeting a particular immune molecule may be associated with an excellent clinical response in most patients, an unexpected autoimmune response may arise in some cases.

SUMMARY

As the use of biological therapies expands, the number and diversity of induced autoimmune disorders should be expected to increase. Paradoxically, for many of these drug-related processes, current treatment indications include the very biological agent producing the adverse event.

Drug-induced inflammatory bowel disease and IBD-like conditions

The pathogenesis of inflammatory bowel disease (IBD) is multifactorial and results from an interaction between genetic, immunologic, microbial, and environmental factors. Certain drugs could act as a trigger for the disease and have been implicated in the development of new onset IBD in a number a studies. These relationships are based on case reports and cohort studies, as proving this in the context of randomized controlled trials would be difficult. Drugs that have been linked to causing or worsening IBD include isotretinoin, antibiotics, nonsteroidal antiinflammatory drugs, oral contraceptives, mycophenolate mofetil, etanercept, ipilimumab, and rituximab. Bowel preparation for colonoscopy has also been associated with aphthoid lesions that may be confused with IBD. However, given the source of these reports we have to be cautious in the interpretation of the data before concluding that these drugs trigger IBD and what is being observed is not related to other confounding factors. Different pathogenic mechanisms have been suggested for the different drugs listed above. In order to clarify the confusion a comprehensive literature review was performed with the goal of advancing the knowledge on this subject.