How gut microbiota may impact ocular surface homeostasis and related disorders

Changes in the bacterial flora in the gut, also described as gut microbiota, are readily acknowledged to be associated with several systemic diseases, especially those with an inflammatory, neuronal, psychological or hormonal factor involved in the pathogenesis and/or the perception of the disease. Maintaining ocular surface homeostasis is also based on all these four factors, and there is accumulating evidence in the literature on the relationship between gut microbiota and ocular surface diseases. The mechanisms involved are mostly interconnected due to the interaction of central and peripheral neuronal networks, inflammatory effectors and the hormonal system. A better understanding of the influence of the gut microbiota on the maintenance of ocular surface homeostasis, and on the onset or persistence of ocular surface disorders could bring new insights and help elucidate the epidemiology and pathology of ocular surface dynamics in health and disease. Revealing the exact nature of these associations could be of paramount importance for developing a holistic approach using highly promising new therapeutic strategies targeting ocular surface diseases.

Diagnostic prediction of gastrointestinal graft-versus-host disease based on a clinical- CT- signs nomogram model

OBJECTIVE

Gastrointestinal graft-versus-host disease (GI-GVHD) is one of the complications that can easily occur after hematopoietic stem cell transplantation (HSCT). Timely diagnosis and treatment are pivotal factors that greatly influence the prognosis of patients. However, the current diagnostic method lacks adequate non-invasive diagnostic tools.

METHODS

A total of 190 patients who suspected GI-GVHD were retrospectively included and divided into training set (n = 114) and testing set (n = 76) according to their discharge time. Least absolute shrinkage and selection operator (LASSO) regression was used to screen for clinically independent predictors. Based on the logistic regression results, both computed tomography (CT) signs and clinically independent predictors were integrated in order to build the nomogram, while the testing set was verified independently. The receiver operating characteristic (ROC), area under the curve (AUC), decision curve, and clinical impact curve were used to measure the accuracy of prediction, clinical net benefit, and consistency of diagnostic factors.

RESULTS

Four key factors, including II-IV acute graft-versus-host disease (aGVHD), the circular target sign, multifocal intestinal inflammation, and an increased in total bilirubin, were identified. The combined model, which was constructed from CT signs and clinical factors, showed higher predictive performances. The AUC, sensitivity, and specificity of the training set were 0.867, 0.787, and 0.811, respectively. Decision curve analysis (DCA), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) showed that the developed model exhibited a better prediction accuracy than the others.

CONCLUSIONS

This combined model facilitates timely diagnosis and treatment and subsequently improves survival and overall outcomes in patients with GI-GVHD.

CRITICAL RELEVANCE STATEMENT

GI-GVHD is one of the complications that can easily occur after HSCT. However, the current diagnostic approach lacks adequate non-invasive diagnostic methods. This non-invasive combined model facilitates timely treatment and subsequently improves patients with GI-GVHD survival and overall outcomes.

KEY POINTS

• There is currently lacking of non-invasive diagnostic methods for GI-GVHD. • Four clinical CT signs are the independent predictors for GI-GVHD. • Association between the CT signs with clinical factors may improve the diagnostic performance of GI-GVHD.

Multi-parametric MRI in the diagnosis and scoring of gastrointestinal acute graft-versus-host disease

OBJECTIVES

Acute gastrointestinal graft-versus-host disease (GI-aGVHD) is a severe complication of allogeneic hematopoietic stem cell transplantation (HSCT). Diagnosis relies on clinical, endoscopic, and pathological investigations. Our purpose is to assess the value of magnetic resonance imaging (MRI) in the diagnosis, staging, and prediction of GI-aGVHD-related mortality.

METHODS

Twenty-one hematological patients who underwent MRI for clinical suspicion of acute GI-GVHD were retrospectively selected. Three independent radiologists, blinded to the clinical findings, reanalyzed MRI images. The GI tract was evaluated from stomach to rectum by analyzing fifteen MRI signs suggestive of intestinal and peritoneal inflammation. All selected patients underwent colonoscopy with biopsies. Disease severity was determined on the basis of clinical criteria, identifying 4 stages of increasing severity. Disease-related mortality was also assessed.

RESULTS

The diagnosis of GI-aGVHD was histologically confirmed with biopsy in 13 patients (61.9%). Using 6 major signs (diagnostic score), MRI showed 84.6% sensitivity and 100% specificity in identifying GI-aGVHD (AUC = 0.962; 95% confidence interval 0.891-1). The proximal, middle, and distal ileum were the segments most frequently affected by the disease (84.6%). Using all 15 signs of inflammation (severity score), MRI showed 100% sensitivity and 90% specificity for 1-month related mortality. No correlation with the clinical score was found.

CONCLUSION

MRI has proved to be an effective tool for diagnosing and scoring GI-aGVHD, with a high prognostic value. If larger studies will confirm these results, MRI could partly replace endoscopy, thus becoming the primary diagnostic tool for GI-aGVHD, being more complete, less invasive, and more easily repeatable.

KEY POINTS

• We have developed a new promising MRI diagnostic score for GI-aGVHD with a sensitivity of 84.6% and specificity of 100%; results are to be confirmed by larger multicentric studies. • This MRI diagnostic score is based on the six MRI signs most frequently associated with GI-aGVHD: small-bowel inflammatory involvement, bowel wall stratification on T2-w images, wall stratification on post-contrast T1-w images, ascites, and edema of retroperitoneal fat and declivous soft tissues. • A broader MRI severity score based on 15 MRI signs showed no correlation with clinical staging but high prognostic value (100% sensitivity, 90% specificity for 1-month related mortality); these results also need to be confirmed by larger studies.

Gastrointestinal Manifestations of Immunodeficiency: Imaging Spectrum

There is a wide spectrum of hereditary and acquired immunodeficiency disorders that are characterized by specific abnormalities involving a plethora of humoral, cellular, and phagocytic immunologic pathways. These include distinctive primary immunodeficiency syndromes due to characteristic genetic defects and secondary immunodeficiency syndromes, such as AIDS from HIV infection and therapy-related immunosuppression in patients with cancers or a solid organ or stem cell transplant. The gut mucosa and gut-associated lymphoid tissue (the largest lymphoid organ in the body), along with diverse commensal microbiota, play complex and critical roles in development and modulation of the immune system. Thus, myriad gastrointestinal (GI) symptoms are common in immunocompromised patients and may be due to inflammatory conditions (graft versus host disease, neutropenic enterocolitis, or HIV-related proctocolitis), opportunistic infections (viral, bacterial, fungal, or protozoal), or malignancies (Kaposi sarcoma, lymphoma, posttransplant lymphoproliferative disorder, or anal cancer). GI tract involvement in immunodeficient patients contributes to significant morbidity and mortality. Along with endoscopy and histopathologic evaluation, imaging plays an integral role in detection, localization, characterization, and distinction of GI tract manifestations of various immunodeficiency syndromes and their complications. Select disorders demonstrate characteristic findings at fluoroscopy, CT, US, and MRI that permit timely and accurate diagnosis. While neutropenic enterocolitis affects the terminal ileum and right colon and occurs in patients receiving chemotherapy for hematologic malignancies, Kaposi sarcoma commonly manifests as bull's-eye lesions in the stomach and duodenum. Imaging is invaluable in treatment follow-up and long-term surveillance as well. Online supplemental material is available for this article. ^©RSNA, 2022.

Pneumatosis intestinalis after hematopoietic stem cell transplantation: When not doing anything is good enough

BACKGROUND/PURPOSE

Pneumatosis intestinalis (PI) has been reported in hematopoietic stem cell transplant recipients (HSCT) since 1980s and at present there is no uniform consensus of the significance and management of this condition.

METHODS

We retrospectively reviewed medical records of 990 consecutive pediatric HSCT recipients and examined data for clinical PI presentation, management and outcomes RESULTS: PI was identified in 53 patients (5.4%), mainly allogeneic HSCT recipients receiving systemic steroids. Abdominal X-ray was the main diagnostic modality. Forty-seven patients (89%) were evaluated because of clinical concerns and others were identified as incidental findings. Pneumoperitoneum was reported in 15 patients (28%). None of these patients had signs of acute abdomen. The majority of patients (43/53, 81%) had no targeted clinical intervention for PI and resolved PI in a median of 15 days (IQR 3-61). Surgery consult was only requested for 7/53 (13%) patients, three of whom had evidence of pneumoperitoneum. None of these patients required any surgical interventions.

CONCLUSIONS

Pneumatosis intestinalis commonly occurs in HSCT recipient receiving steroids, but unlike with NEC, PI rarely poses clinical risk after transplant. The majority of HSCT recipients with PI require only close monitoring without interventions. Surgical evaluation should be based on clinical symptoms and not PI presence alone.

Early Diagnosis of Neutropenic Enterocolitis by Bedside Ultrasound in Hematological Malignancies: A Prospective Study

(1) Background: Neutropenic enterocolitis (NEC) is a life-threatening complication following chemotherapy with high mortality rates. Early diagnosis is crucial to improve outcomes. We designed a large prospective study employing bedside ultrasonography (US) as a novel approach to allow early diagnosis and prompt treatment to reduce mortality. (2) Methods: NEC was defined as US or computed tomography (CT)-proven bowel wall thickness ≥ 4 mm at the onset of at least one of the following symptoms: fever and/or abdominal pain and/or diarrhea during neutropenia. From 2007 to 2018, 1754 consecutive patients underwent baseline bedside US that was invariably repeated within 12 h from the onset of symptom(s) suggestive of NEC. (3) Results: Overall, 117 episodes of NEC were observed, and overall mortality was 9.4%. Bowel wall thickening was invariably absent in the negative control group. Abdominal pain associated with one or more symptoms correlated with the highest relative risk (17.33), sensitivity (89.7%), specificity (100%), and accuracy (96.2%) for diagnosis. The combination of abdominal pain and fever at onset significantly correlated with worse survival (p < 0.0001, OR 13.85). BWT (p = 0.046), type of therapy (p = 0.049) and blood culture positivity (p = 0.003) correlated with worse survival. (4) Conclusions: Bedside ultrasound is a non-invasive and radiation free imaging technique for early diagnosis of NEC and its prompt treatment significantly reduced mortality.

Mortality After General Surgery Among Hospitalized Patients With Hematologic Malignancy

BACKGROUND

Hospitalized patients with hematologic malignancies (HMs) may require abdominal operations for complications of malignancy, treatment sequelae, or unrelated abdominal pathology. We determined predictors of mortality after emergency general surgery for patients with HM using national-level data.

MATERIALS AND METHODS

We analyzed the 2010-2014 National Inpatient Sample for International Classification of Disease, Ninth Revision, Clinical Modification codes for HM and abdominal operations, comparing adult patient encounters with abdominal operations with HM to those without HM. Multivariate logistic regression was performed to identify predictors of mortality.

RESULTS

Of the 7.9 million adult inpatient encounters where abdominal surgery was performed, 82,187 (1%) had concomitant diagnoses of HM. Mortality among patient encounters with HM was significantly higher than without HM (9.0% versus 2.0%; P < 0.0001). Patient encounters with HM and surgery and a diagnosis of acute abdominal pain had mortality rates as high as 41%. The median standardized risk ratio for death after the top 25 general surgery procedures was 2.9 (interquartile range: 2.2-3.8) among patients with HM. In adjusted analyses, odds of mortality among patients with HM undergoing surgery were increased by concomitant acute abdominal pain diagnosis (odds ratio [OR] = 2.6; P < 0.0001), coagulopathy (OR = 2.0; P < 0.0001), aplastic anemia (OR = 1.7; P < 0.0001), peripheral vascular disease (OR = 1.4; P = 0.001), and weight loss (OR = 1.3; P < 0.0001).

CONCLUSIONS

Although uncommon, surgery on patients with HM is associated with mortality rates nearly five times higher than the general surgical population. Patients with HM requiring surgical intervention may be at particularly high odds of death and postoperative complications.

Treatment with Apocynin Limits the Development of Acute Graft-versus-Host Disease in Mice

Graft-versus-host disease (GVHD) is the most serious complication limiting the clinical utility of allogeneic hematopoietic stem cell transplantation (HSCT), in which lymphocytes of donors (graft) are activated in response to the host antigen. This disease is associated with increased inflammatory response through the release of inflammatory mediators such as cytokines, chemokines, and reactive oxygen species (ROS). In this study, we have evaluated the role of ROS in GVHD pathogenesis by treatment of recipient mice with apocynin (apo), an inhibitor of intracellular translocation of cytosolic components of NADPH oxidase complex. The pharmacological blockade of NADPH oxidase resulted in prolonged survival and reduced GVHD clinical score. This reduction in GVHD was associated with reduced levels of ROS and TBARS in target organs of GVHD in apocynin-treated mice at the onset of the mortality phase. These results correlated with reduced intestinal and liver injuries and decreased levels of proinflammatory cytokines and chemokines. Mechanistically, pharmacological blockade of the NADPH oxidase was associated with inhibition of recruitment and accumulation of leukocytes in the target organs. Additionally, the chimerism remained unaffected after treatment with apocynin. Our study demonstrates that ROS plays an important role in mediating GVHD, suggesting that strategies aimed at blocking ROS production may be useful as an adjuvant therapy in patients subjected to bone marrow transplantation.

Isolation of Lamina Propria Mononuclear Cells from Murine Colon Using Collagenase E

The intestine is the home to the largest number of immune cells in the body. The small and large intestinal immune systems police exposure to exogenous antigens and modulate responses to potent microbially derived immune stimuli. For this reason, the intestine is a major target site of immune dysregulation and inflammation in many diseases including but, not limited to inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, graft-versus-host disease (GVHD) after bone marrow transplantation (BMT), and many allergic and infectious conditions. Murine models of gastrointestinal inflammation and colitis are heavily used to study GI complications and to pre-clinically optimize strategies for prevention and treatment. Data gleaned from these models via isolation and phenotypic analysis of immune cells from the intestine is critical to further immune understanding that can be applied to ameliorate gastrointestinal and systemic inflammatory disorders. This report describes a highly effective protocol for the isolation of mononuclear cells (MNC) from the colon using a mixed silica-based density gradient interface. This method reproducibly isolates a significant number of viable leukocytes while minimizing contaminating debris, allowing subsequent immune phenotyping by flow cytometry or other methods.

Incubation of Immune Cell Grafts With MAX.16H5 IgG1 Anti-Human CD4 Antibody Prolonged Survival After Hematopoietic Stem Cell Transplantation in a Mouse Model for Fms Like Tyrosine Kinase 3 Positive Acute Myeloid Leukemia

Despite the constant development of innovative therapeutic options for hematological malignancies, the gold-standard therapy regimen for curative treatment often includes allogeneic hematopoietic stem cell transplantation (HSCT). The graft-vs.-leukemia effect (GVL) is one of the main therapeutic goals that arises from HSCT. On the other hand, graft-vs.-host disease (GVHD) is still one of the main and most serious complications following allogeneic HSCT. In acute myeloid leukemia (AML), HSCT together with high-dose chemotherapy is used as a treatment option. An aggressive progression of the disease, a decreased response to treatment, and a poor prognosis are connected to internal tandem duplication (ITD) mutations in the Fms like tyrosine kinase 3 (FLT3) gene, which affects around 30% of AML patients. In this study, C3H/HeN mice received an allogeneic graft together with 32D-FLT3^ITD AML cells to induce acute GVHD and GVL. It was examined if pre-incubation of the graft with the anti-human cluster of differentiation (CD) 4 antibody MAX.16H5 IgG₁ prevented the development of GVHD and whether the graft function was impaired. Animals receiving grafts pre-incubated with the antibody together with FLT3^ITD AML cells survived significantly longer than mice receiving untreated grafts. The observed prolonged survival due to MAX.16H5 incubation of immune cell grafts prior to transplantation may allow an extended application of additional targeted strategies in the treatment of AML.

Unintended Consequences of Systemic and Ablative Oncologic Therapy in the Abdomen and Pelvis

Human cancers are genetically complex and diverse. Although advances in oncologic therapy aim to define and target unique steps in carcinogenesis, oncologists often rely on less discriminate anticancer therapies that have consequences for normal tissues. Even many of the so-called targeted therapies currently employed can adversely affect normal cells, leading to complications that necessitate dose reductions or cessation of specific therapies. This article explores the unintended consequences of currently employed systemic and ablative anticancer therapies that might manifest at imaging examinations of the abdomen and pelvis, including cytotoxic, molecular targeted, and immunologic agents; ablation; and hematopoietic stem cell transplant. Each of these treatments can have both major and minor unintended effects in the targeted organ(s), in local or adjacent structures, or at distant sites. Timely detection and reporting of adverse consequences of anticancer therapies by the astute imager can result in critical treatment modifications and/or lifesaving interventions; therefore, knowledge of these unintended effects is paramount for radiologists interpreting the results of imaging examinations in cancer patients. ^©RSNA, 2018.

Surgical treatment of intestinal complications of graft versus host disease in the pediatric population: Case series and review of literature

BACKGROUND/PURPOSE

Intestinal complications of acute graft-versus-host disease (aGVHD) include hemorrhage and perforation in the short-term, and stricture with bowel obstruction in the long-term. As medical management of severe aGVHD has improved, more patients are surviving even advanced stages of intestinal aGVHD. This review summarizes the available pediatric literature on surgical treatment of complications of intestinal GVHD.

METHODS

A systematic review was performed using PubMed, Cochrane, Embase, and Scopus databases. Any publication that addressed surgical treatment of acute and chronic intestinal GVHD in the pediatric population was reviewed in detail. Furthermore, we included information on 5 additional patients from the institutions of this review's authors, which had not been previously published.

RESULTS

We identified 8 studies, comprising 13 patients. Surgical interventions were undertaken for a variety of intestinal GVHD complications, including small bowel obstruction owing to stricture (n=8), enterocutaneous fistulae (n=2), gastrointestinal hemorrhage/perforation (n=1 each), and esophageal stricture (n=1). Among eight patients with bowel obstruction as an indication, pathology revealed ulceration with fibrosis in all but one; 3 had signs of persistent GVHD. Surgical mortality was reported in 4 patients (31%) at an average of 6weeks postoperatively. The median overall follow-up time was 20months (IQR, 2-21).

CONCLUSIONS

Although intestinal aGVHD management is almost exclusively medical, a small subset of patients develops complications of intestinal GVHD that require surgical intervention. With expanding indications for stem cell transplantation as well as improved survival after previously fatal bouts of intestinal aGVHD, it is likely that surgical intervention will become more common in these complicated patients.

SYSTEMATIC REVIEW

Level of Evidence: Level IV.

Diarrhea after allogeneic stem cell transplantation: beyond graft-versus-host disease

Diarrhea constitutes a frequent and often debilitating complication of allogeneic hematopoietic cell transplantation (alloHCT). Especially when accompanied by jaundice, skin rash, and symptoms of the upper gastrointestinal tract, diarrhea strongly suggests emergence of acute graft-versus-host disease (GvHD), which is a serious immune complication of the procedure, with possible fatal consequences. However, especially when diarrhea occurs as an isolated symptom, the other causes must be excluded before initiation of GvHD treatment with immune-suppressive drugs. In this article, a broad overview of the literature of different causes of diarrhea in the setting of alloHCT is provided, revealing causes and presentations different from those observed in the general population. We discuss gastrointestinal GvHD with a special focus on biomarkers, but also uncover underlying infectious: viral, bacterial, and parasitic as well as toxic causes of diarrhea. Finally, we suggest a practical algorithm of approach to patients with diarrhea after alloHCT, which may help to establish a proper diagnosis and initiate a causative treatment.

Role of Ultrasound in Complications of Hematopoetic Stem Cell Transplantation

Hematopoetic stem cell transplantation (HSCT) is an established therapeutic option for both malignant and nonmalignant indications, whose incidence has continued to increase in recent years. Because of its lower cost and lack of radiation exposure, ultrasound examination is often the first-line imaging modality in evaluating patients both before and after HSCT. It is important for radiologists to be aware of sonographic manifestations of the complications that may arise from HSCT. In this study, we will review the basics of HSCT, the role of imaging, and ultrasound examination findings in common and uncommon complications arising from HSCT.

Attenuation of graft-versus-host-disease in NOD scid IL-2Rγ(-/-) (NSG) mice by ex vivo modulation of human CD4(+) T cells

NOD.Cg-Prkdc(scid) IL-2rg(tm1Wjl) /SzJ (NSG) mice are a valuable tool for studying Graft-versus-Host-Disease (GvHD) induced by human immune cells. We used a model of acute GvHD by transfer of human peripheral blood mononuclear cells (PBMCs) into NSG mice. The severity of GvHD was reflected by weight loss and was associated with engraftment of human cells and the expansion of leukocytes, particularly granulocytes and monocytes. Pre-treatment of PBMCs with the anti-human CD4 antibody MAX.16H5 IgG1 or IgG4 attenuated GvHD. The transplantation of 2 × 10(7) PBMCs without anti-human CD4 pre-treatment induced a severe GvHD (0% survival). In animals receiving 2 × 10(7) PBMCs pre-incubated with MAX.16H5 IgG1 or IgG4, GvHD development was reduced and survival was increased. Immune reconstitution was measured by flow cytometry and confirmed for human leukocytes (CD45), CD3(+) /CD8(+) cytotoxic T cells and CD3(+) /CD4(+) T helper cells. Human B cells (CD19) and monocytes (CD14) could not be detected. Histopathological analysis (TUNEL assay) of the gut of recipient animals showed significantly less apoptotic crypt cells in animals receiving a MAX.16H5 IgG1 pre-incubated graft. These findings indicate that pre-incubation of an allogeneic graft with an anti-human CD4 antibody may decrease the frequency and severity of GvHD after hematopoietic stem cell transplantation (HSCT) and the need of conventional immunosuppressive drugs. Moreover, this approach most probably provides a safer HSCT that must be confirmed in appropriate clinical trials in the future. © 2016 International Society for Advancement of Cytometry.

Sonographic Appearance of the Gallbladder in the Allogeneic Hematopoietic Stem Cell Transplant Population

OBJECTIVES

To determine whether gallbladder sonographic findings in hematopoietic stem cell (HSC) transplant patients can distinguish among hepatobiliary complications of HSC transplants (graft-versus-host disease [GVHD] and veno-occlusive disease) and biliary events (cholecystitis, cholangitis, and choledocholithiasis).

METHODS

All HSC transplant patients who underwent gallbladder sonography from 2009 through 2012 were identified. Complications and sonographic findings were recorded.

RESULTS

Of 124 patients, 66 (53.2%) had an event: 33 (50.0%) had GVHD; 22 (33.3%) had veno-occlusive disease; 6 (9.0%) had a biliary event; 4 (6.0%) had veno-occlusive disease and GVHD; and 1 (1.5%) had veno-occlusive disease and a biliary event. Of all patients, 115 (92.7%) had 1 or more sonographic findings in the gallbladder, with sludge being most common in all groups. In patients with veno-occlusive disease, the second and third most common findings were pericholecystic fluid and wall thickening. In patients with GVHD, distension was the second most common. Patients with biliary events all had distension, and half had pericholecystic fluid. Patients with veno-occlusive disease were significantly more likely to have wall thickening than those with GVHD or no event (77.2% versus 36.3%; P= .005; and 77.2% versus 37.9%; P= .002) and more likely to have pericholecystic fluid than patients with GVHD (95.5% versus 45.5%; P = .0001), a biliary event (95.5% versus 50%; P = .02), or no event (95.5% versus 29.3%; P = .0001). The positive predictive value of any finding was low for all groups because findings were common in patients with no event.

CONCLUSIONS

Sonographic abnormalities of the gallbladder after HSC transplants are common in patients with and without HSC transplant complications and in those with biliary events. No sonographic finding is useful to distinguish among complications in HSC transplant patients.