A case of steroid-dependent myeloid granulocytic sarcoma masquerading as Crohn's disease

Small bowel tumors and Crohn's disease are common causes of small bowel obstruction.Early stage neoplasms can easily be mistaken for Crohn's disease.Therefore,thorough work-ups including imaging studies and endoscopic evaluation with biopsies are critical for accurate diagnosis.Here we report a case of an otherwise healthy female with progressive onset of multiple,recurrent obstructive symptoms secondary to terminal ileal narrowing who was referred for management of steroid-dependent Crohn's disease.After thorough evaluation,the diagnosis was revised to myeloid granulocytic sarcoma involving the terminal ileum.In this case,a delay in diagnosis can be detrimental for prognosis,as myeloid granulocytic sarcoma is highly predictive of underlying acute myeloid leukemia and needs urgent referral for chemotherapy and/or resection.

Immunopathogenesis of inflammatory bowel disease

Crohn＇s disease and ulcerative colitis are chronic relapsing immune mediated disorders that results from an aberrant response to gut luminal antigen in genetically susceptible host. The adaptive immune response that is then triggered was widely considered to be a T-helper-1 mediated condition in Crohn＇s disease and T-helpero2 mediated condition in ulcerative colitis. Recent studies in animal models, genome wide association, and basic science has provided important insights in in the immunopathogenesis of inflammatory bowel disease, one of which was the characterization of the interleukin-23/Th-17 axis.

Immunopathology of inflammatory bowel disease

Inflammatory bowel disease (IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune system. The host microbiome, as well as viruses and fungi, play important roles in the development of IBD either by causing inflammation directly or indirectly through an altered immune system. New technologies have allowed researchers to be able to quantify the various components of the microbiome, which will allow for future developments in the etiology of IBD. Various components of the mucosal immune system are implicated in the pathogenesis of IBD and include intestinal epithelial cells, innate lymphoid cells, cells of the innate (macrophages/monocytes, neutrophils, and dendritic cells) and adaptive (T-cells and B-cells) immune system, and their secreted mediators (cytokines and chemokines). Either a mucosal susceptibility or defect in sampling of gut luminal antigen, possibly through the process of autophagy, leads to activation of innate immune response that may be mediated by enhanced toll-like receptor activity. The antigen presenting cells then mediate the differentiation of naïve T-cells into effector T helper (Th) cells, including Th1, Th2, and Th17, which alter gut homeostasis and lead to IBD. In this review, the effects of these components in the immunopathogenesis of IBD will be discussed.

Optimizing 6-mercaptopurine and azathioprine therapy in the management of inflammatory bowel disease

The thiopurine drugs,6-mercaptopurine(6-MP) and azathioprine,are efficacious in the arsenal of inflammatory bowel disease(IBD) therapy.Previous reports indicate that 6-thioguanine nucleotide(6-TGN) levels correlate with therapeutic efficacy,whereas high 6-methylmercaptopurine(6-MMP) levels are associated with hepatotoxicity and myelotoxicity.Due to their complex metabolism,there is wide individual variation in patient response therein,both in achieving therapeutic drug levels as well as in developing adverse reactions.Several strategies to optimize 6-TGN while minimizing 6-MMP levels have been adopted to administer the thiopurine class of drugs to patients who otherwise would not tolerate these drugs due to side-effects.In this report,we will review different approaches to administer the thiopurine medications,including the administration of 6-mercaptopurine in those unsuccessfully treated with azathioprine;coadministration of thiopurine with allopurinol;co-administration of thiopurine with anti-tumor necrosis factor α;6-TGN administration;desensitization trials;and split dosing of 6-MP.

Insights on the use of biosimilars in the treatment of inflammatory bowel disease

Biologic therapy, such as those that target tumor necrosis factor(TNF) signaling, has proven to be an efficacious method of treatment for patients with inflammatory bowel disease(IBD) with regards to symptom management and mucosal healing. However, the rising prevalence of IBD worldwide and the everincreasing burden of biologic pharmaceuticals in the health care industry is alarming for insurance companies, clinicians, and patients. The impending patent expiry and the relatively high costs of biologics, particularly anti-TNF agents, have paved the way for biosimilar development for IBD. The United States Food and Drug Administration defines a biosimilar as a biological product that is highly similar to its reference medicinal product, with no clinically meaningful differences in terms of safety, purity, and potency. The hope with biosimilars is that their entry into the market will be able to drive competition between pharmaceutical companies to reduce prices like that of the generic market, and that access to appropriate biologic treatments for IBD patients is increased in the long-term. Yet, there are challenging issues such as indication extrapolation and interchangeability that are still being debated in the field of IBD and must be addressed in future issued guidance. This review will discuss the issues and implications concerning the use of biosimilar therapy for IBD.