Academic literature on the topic 'Colitis; Immune pathology'

Inflammatory bowel disease is a group of inflammatory disorders of unknown etiology. Various genetic factors, mucosal immune response, inappropriate activation of immune system driven by the presence of various luminal flora and epithelial defects have been postulated. Crohn disease and Ulcerative colitis are the two most common inflammatory bowel diseases. Since, specific clinical laboratory features are lacking which may help in establishing a diagnosis histopathological diagnosis remains the gold standard. This review highlights the known hypothesis regarding the etiopathogenesis of these two diseases and also describes pertinent histological features.Journal of Pathology of Nepal (2015) Vol. 5, 756-765

Cytokines maintain intestinal health, but precise intercellular communication networks remain poorly understood. Macrophages are immune sentinels of the intestinal tissue and are critical for gut homeostasis. Here, we show that in a murine inflammatory bowel disease (IBD) model based on macrophage-restricted interleukin-10 (IL-10) receptor deficiency (Cx3cr1Cre:Il10rafl/fl mice), proinflammatory mutant gut macrophages cause severe spontaneous colitis resembling the condition observed in children carrying IL-10R mutations. We establish macrophage-derived IL-23 as the driving factor of this pathology. Specifically, we report that Cx3cr1Cre:Il10rafl/fl:Il23afl/fl mice harboring macrophages deficient for both IL-10R and IL-23 are protected from colitis. By analyzing the epithelial response to proinflammatory macrophages, we provide evidence that T cells of colitic animals produce IL-22, which induces epithelial chemokine expression and detrimental neutrophil recruitment. Collectively, we define macrophage-specific contributions to the induction and pathogenesis of colitis, as manifested in mice harboring IL-10R deficiencies and human IBDs.

821 Background: CPI therapy has expanded rapidly in recent years and represents a major advancement in the treatment of many cancers, including hepatocellular carcinoma, gastric cancer, and colon cancer. However, these therapies are associated with significant toxicities. CPI colitis is one of the most common toxicities and can be fatal, especially when not diagnosed and treated promptly. The current gold standard for diagnosis is endoscopy with biopsy, an invasive procedure that is resource- and time-intensive. CT has emerged as a possible alternative. The primary objective of this study is to identify the diagnostic performance of CT in the evaluation of CPI colitis. Methods: With IRB approval, we conducted a retrospective cohort study of patients who received CPI therapy between 2009-2019 across a single healthcare system. Patients were included if they underwent both abdominal CT and upper/lower endoscopy with biopsy within 72 hours of each other. We reviewed the electronic medical record to identify possible cases of colitis based on either CT or pathology. All cases were labeled as either true positive or false positive based on pathology. We examined clinical characteristics, including CTCAE grade and treatment received. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT for diagnosing CPI colitis when compared to the gold standard of tissue diagnosis. Results: Of the 4,474 patients screened, 141 met inclusion criteria. Average age was 63 years (23 – 91); 43% were male. Most common tumor types were melanoma (36%) and NSCLC (20%). Seventy-four percent of patients were treated with anti-PD-1/PD-L1 monotherapy. Forty percent had signs of colitis on CT scan and 59% had biopsy-proven CPI colitis. Sensitivity and specificity of CT were 51% and 74%, respectively. PPV of CT was 74% and NPV was 51%. Of those with confirmed CPI colitis, 78% had symptoms that were classified as grade 3 or above. Seventy-three percent received IV steroids and 38% received infliximab. Conclusions: CT demonstrates moderate specificity and PPV and remains an important diagnostic test but does not replace endoscopy/biopsy in the evaluation of CPI colitis.

Abstract Background Intestinal homeostasis depends on the interplay between the gut microbiota, epithelium and immune cells. A novel role of Oncostatin M (OSM), a pro-inflammatory cytokine has recently been identified in mouse and human intestinal inflammation. Previous studies have shown OSM as a key driver of chronic inflammation in anti-TNF-α-refractory colitis. A single-nucleotide polymorphism in the human OSM genetic locus is strongly associated with risk of developing inflammatory bowel disease (IBD), thus, biological therapies targeting OSM could have therapeutic potential. Our project aims to explore the impact of OSM on intestinal barrier function in health and disease. Methods To evaluate the role of OSM in intestinal inflammation, we utilized a combination of in vitro and in vivo techniques. This included the generation of 3D intestinal organoids from mice and patients. Organoids were stimulated with a repertoire of different cytokines to determine the responsiveness of OSM receptor (OSMR) to different cytokine signals using a quantitative-PCR-based approach. For in vivo modelling of disease, the Helicobacter hepaticus colitis model was used, as it combines both immune and dysbiosis-driven aspects of disease. This allowed us to measure OSM and OSMR expression in response to inflammation and within specific organs and cell subsets. Furthermore, RNAscope in situ hybridisation was used to determine the localisation of OSM- and OSMR-expressing cells in inflamed mucosal tissue from colitic mice and IBD patients. Results RNAscope in situ hybridisation as well as gene expression analysis have shown that the OSM and OSMR were highly expressed in C57BL/6 mice upon induction of colitis in the H. hepaticus model of disease and in mucosal tissues of IBD patients. In addition, a plethora of pro-inflammatory cytokines were upregulated during colitis, with colitic mice showing increased tissue pathology. Furthermore, FACS analysis shows excessive immune cell infiltration in the spleen, colon and mesenteric lymph nodes of colitic mice. Conclusion Our preliminary results have shown that different gut-resident hematopoietic and non-hematopoietic cell types express OSM and OSMR and this expression was modulated by pro-inflammatory cytokines. We therefore hypothesis that OSM might drive distinct transcriptional responses in various gut-resident cell populations. Thus, differential targeting of the OSM receptor might be a potential therapeutic approach in IBD.

Abstract Introduction: Idelalisib (IDELA) is a targeted PI3Kd inhibitor approved for the treatment of patients (pts) with relapsed CLL/FL. The established toxicity profile of IDELA includes diarrhea/colitis with a grade ≥3 incidence of ~15%. Here, we present the histopathological-as well as immune profiling and viral testing-results of gastrointestinal tissue specimens from pts who received diagnostic biopsies for abdominal pain or diarrhea during treatment with IDELA. Methods: Intestinal biopsy specimens obtained from 31 pts during treatment with IDELA across 10 trials (monotherapy n = 3 or in combination with: rituximab n = 9; ofatumumab n = 14; and bendamustine/rituximab n = 5) were reviewed separately by 2 independent pathologists with expertise in the area of gastrointestinal and transplant pathology. If more than 1 biopsy time point per pt was available (n = 3), all time points would be evaluated and, if discordant, would be reported separately. Evaluation included hematoxylin and eosin stain; and immunohistochemistry (IHC) for CD3, CD8, FOXP3, CD79a, CMV, and adenovirus (as adequate tissue allowed). Additionally, droplet digital PCR (ddPCR) was performed for cytomegalovirus (CMV), adenovirus, and human herpesvirus 6 (HHV-6). Colon/small bowel tissues from 18 normal individuals who underwent biopsy during routine screening colonoscopy and had normal pathology results were included as controls. Results: Baseline characteristics of pts included CLL n = 24 (77.4%) and iNHL n = 7 (22.6%), age range 50 to 82 years with median 65.6 years, male n = 19 (61.3%). IDELA median dose = 150 mg BID. Diarrhea/colitis (Grade 1-3) was reported in 24 cases (75%) including 1 case of hemorrhagic colitis. One patient each had concurrent laboratory-confirmed Mycobacterium avium-intracellulare and norovirus and 2 patients were excluded from histomorphological analysis, 1 due to celiac disease and 1 due to total loss of glands secondary to CMV. Four distinct morphological patterns were identified: 1) predominantly normal, 2) apoptotic, 3) inflammatory/ischemic, and 4) mixed apoptotic/inflammatory/ischemic. CMV IHC was performed in all 31 cases; 2 showed strong/moderate positivity, and 2 were weakly positive. Adenovirus IHC was performed on 29 specimens, and 1 was weakly positive. ddPCR performed on 27 formalin-fixed paraffin-embedded tissues identified 6 positive CMV cases (including all 4 IHC+ cases), 0 adenovirus cases, and 1 HHV-6-positive case. Among the CMV cases, the most common pattern was mixed, seen in 4 of 6 cases, whereas the most common morphologic feature was apoptosis, seen in 5 of 6 cases. A summary of findings is shown in Table 1. Conclusion: In this subset of pts who underwent intestinal biopsy during IDELA clinical trials, most biopsies (87%) were performed in the context of ongoing diarrhea/colitis and the majority of tissue samples (90%) revealed some component of inflammation. Immune profiling by IHC showed increased Tregs in patterns associated with glandular destruction. Immunohistochemistry and ddPCR for virus in conjunction with microbiology studies revealed that in 28% of these cases, a pathogen was identified. This dataset suggests that in a significant number of cases, idelalisib-associated diarrhea/colitis may be due to an infectious etiology secondary to immune dysfunction that results in either an inflammatory/ischemic or a mixed histologic pattern; however, the majority of these cases have no identifiable infectious etiology. Based on these findings, we recommend that a workup of pts with idelalisib-associated diarrhea/colitis should include a complete evaluation for infectious causes including intestinal biopsy when a pathogen is elusive with standard testing. Disclosures Yeung: Gilead Sciences: Research Funding. Hockenbery:Gilead Sciences: Research Funding. Coutre:Gilead Sciences: Consultancy, Research Funding. Dubowy:Gilead Sciences: Employment, Equity Ownership. Marcondes:Gilead Sciences: Employment, Equity Ownership. Munugalavadla:Gilead Sciences: Employment, Equity Ownership. Bosch:Gilead Sciences: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Research Funding.

e15102 Background: Immune checkpoint inhibitors (ICIs) are efficacious in treating many advanced malignancies. However, drug induced colitis limits their use significantly. We present cases with chronic refractory ICI colitis requiring long term immunosuppressive therapy and favorable cancer outcomes. Methods: We identified 3 cases who developed ICI colitis and persisted for longer than 6 months requiring long term immunosuppressant therapy. The patients’ clinical data was collected. Results: All patients were male, with median age of 55. Two had melanoma, one urothelial cancer. All patients received PD-1(L)-1 agents with colitis onset about 3-6 months after ICI treatment. All patients were taken off ICI permanently due to colitis over a duration of 19-30 months (peak grade of 3). Endoscopy of all three were grossly unremarkable, with lymphocytic colitis on pathology in all three. Patient A’s colitis achieved clinical and histological remission after 5 doses of vedolizumab, however recurred after 9 months with biopsy proven recurrence. Current management is anti-diarrheal medication given mild symptom. Patient B had more aggressive disease, with first recurrence after 2 doses of infliximab and steroid, achieved initial histological remission after 3 doses of vedolizumab and 2 additional infliximab, then had 2nd recurrence after 3 months. Fecal microbiota transplantation as compassionate treatment was not effective. Thereafter, patient was resumed on vedolizumab ever since with clinical remission. Last histology evaluation showed persistent lymphocytic colitis 30 months after initial diagnosis. The third case had initial histological remission after 3 doses of vedolizumab, followed by recurrence after 4 months, which triggered another 3 doses of vedolizumab, with persistent grade 3 diarrhea despite resolution of histological inflammation after total 6 doses of vedolizumab. Patient was subsequently treated with steroid and ustekinumab with clinical remission. At the end of follow up, all three patients have sustained cancer remission over 19-31 months. Conclusions: IMC is a common adverse event from ICI, and could progress to a chronic inflammatory condition that require long term treatment. Histological remission does not preclude future recurrence of colitis. Persistent toxicity could be a surrogate marker for enduring ICI effect which may be associated with favorable cancer outcome. Long term immunosuppression can be essential for refractory ICI colitis cases for clinical remission.

Seventy-three patients with pathologic liver function tests were examined using ultrasound one day prior to liver biopsy. The ultrasound findings were compared with the histologic findings. In 23 patients enlarged lymph nodes were found in the hepato-duodenal ligament and 21 of these had active immune-mediated liver disease. Of the remaining 2 patients one had ulcerative colitis (and fatty liver) and one chronic cholecystitis (and ***haemosiderosis). Of the 33 patients with biopsy-proven active ***immune-mediated liver disease 21 had pathologic lymph nodes in the hepato-duodenal ligament at ultrasound. It was not possible to identify the ligament in 8 patients and in the remaining 4 no pathologic lymph nodes could be found. Twenty-one of these patients had normal liver echoes on ultrasound, 5 exhibited increased echogenicity and 5 had heterogeneous echogenicity. In a further 2 patients both increased echogenicity and heterogeneous parenchyma were found. Ultrasound examination of the liver parenchyma alone would thus lead to 21 of the 33 patients being classified as normal and a further 5 being classified as having fatty changes of the liver. Only 7 would be regarded as having significant liver pathology. However, if demonstration at ultrasound of pathologic lymph nodes in the hepato-duodenal ligament is regarded as being consistent with significant hepatic pathology a further 15 patients could be added to these 7 patients, giving a total of 22 out of 33 patients (67%) identified as having significant liver pathology using ultrasound alone. The reliability of ultrasound in the diagnosis of immune-mediated liver disease can thus be improved considerably by actively searching for lymph nodes in the hepato-duodenal ligament.

Angiogenesis is now understood to play a major role in the pathology of chronic inflammatory diseases and is indicated to exacerbate disease pathology. Recent evidence shows that angiogenesis is crucial during inflammatory bowel disease (IBD) and in experimental models of colitis. Examination of the relationship between angiogenesis and inflammation in experimental colitis shows that initiating factors for these responses simultaneously increase as disease progresses and correlate in magnitude. Recent studies show that inhibition of the inflammatory response attenuates angiogenesis to a similar degree and, importantly, that inhibition of angiogenesis does the same to inflammation. Recent data provide evidence that differential regulation of the angiogenic mediators involved in IBD-associated chronic inflammation is the root of this pathological angiogenesis. Many factors are involved in this phenomenon, including growth factors/cytokines, chemokines, adhesion molecules, integrins, matrix-associated molecules, and signaling targets. These factors are produced by various vascular, inflammatory, and immune cell types that are involved in IBD pathology. Moreover, recent studies provide evidence that antiangiogenic therapy is a novel and effective approach for IBD treatment. Here we review the role of pathological angiogenesis during IBD and experimental colitis and discuss the therapeutic avenues this recent knowledge has revealed.

The review is devoted to erythema nodosum (UE), which is a typical variant of septal panniculitis without vasculitis and is a nonspecific immune inflammatory syndrome. Often, UE acts as one of the symptoms of systemic pathology, including rheumatic diseases (RH), sarcoidosis, Crohn’s disease, ulcerative colitis, cancer, etc., which can cause late diagnosis and, accordingly, the appointment of adequate therapy.