The gastrointestinal tract: properties and role in allogeneic hematopoietic stem cell transplantation

High rate of adenovirus detection in gastrointestinal biopsies of symptomatic stem cell transplant recipients

OBJECTIVES

The gastrointestinal (GI) tract is a major human adenovirus (HAdV) replication site in patients undergoing hematopoietic stem cell transplantation (HSCT), yet the prevalence and correlates of HAdV GI infection in this setting have remained poorly recognized, especially among adult HSCT recipients.

DESIGN OR METHODS

We retrospectively studied the prevalence and risk factors of HAdV GI-tissue infection in HSCT recipients (73 adults and 15 children) with GI symptoms who underwent GI-tissue biopsy between January-2012 and December-2017. The presence of HAdV in the GI tissues was determined by real-time PCR.

RESULTS

HAdV GI-tissue infection was detected in 21 (23.9%) patients, with similar infection rates identified in adults and children. GI-tissue detection was more common at late (>100 days) compared to early times post-transplantation (50% vs. 12.9%, p < .001). The presence of bloody diarrhea, Arab ethnicity (p = .014) and concurrent cytomegalovirus GI-tissue detection (p = .025) were significantly correlated with HAdV GI-tissue infection, while chronic graft versus host disease was of borderline association (p = .055).

CONCLUSIONS

Our findings reveal a high rate and new clinical-demographic correlates of HAdV GI-tissue infection in adult and pediatric HSCT recipients with GI symptoms. The findings highlight the need for future prospective studies to assess the relatedness of HAdV infection to the GI symptoms, and the prevalence, impact, and treatment of HAdV GI infection in HSCT recipients.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation

INTRODUCTION

Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality.

AREAS COVERED

This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials.

EXPERT OPINION

Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

Immune-mediated enteropathies: From bench to bedside

Immune-mediated enteropathies are caused by excessive reactions of the intestinal immune system towards non-pathogenic molecules. Enteropathy leads to malabsorption-related symptoms and include (severe) chronic diarrhea, weight loss and vitamin deficiencies. Parenteral feeding and immunosuppressive therapy are needed in severe cases. Celiac disease has long been recognized as the most common immune-mediated enteropathy in adults, but the spectrum of immune-mediated enteropathies has been expanding. Histological and clinical features are sometimes shared among these enteropathies, and therefore it may be challenging to differentiate between them. Here, we provide an overview of immune-mediated enteropathies focused on clinical presentation, establishing diagnosis, immunopathogenesis, and treatment options.

Oral nutritional support to adult patients with acute intestinal Graft Versus Host Disease (GVHD): A proposal for dietary intervention as a model to clinical trials

BACKGROUND

Acute Graft Versus Host Disease (GVHD) affects about 20%-80% of the patients after the hematopoietic stem cell transplant (HSCT) and it is amongst the main causes of morbidity and mortality both in children and adults. The intestine is one of the most affected organs by GVHD causing important alterations in the nutritional status and quality of life, considering that the dysfunctional intestine could decrease food intake as well as an inappropriate dietary plan could worsen the clinical condition. In addition to GVHD, chemotherapy conditioning regimen suppresses the immune system, promotes mucositis and increases the risk of infectious complications. Taking the above into consideration, when per oral diet is possible; the food choices should be carefully planned and monitored to promote nutritional support and avoid worsening the intestinal function and clinical condition.

OBJECTIVE

This work was aimed to present a practice guideline proposal, to be validated, based on literature review, regarding to oral dietary recommendations for acute intestinal GVHD after HTSC.

METHODS

Two research phases were defined: Phase one: evidence-based literature review; Phase 2: Practice Guideline Proposal. 1: Evidence based literature review SEARCH METHODS: A literature review (1997-2019) was performed including PubMed, in English, and Lilacs, in Portuguese electronic database to address the subject of dietary intervention for intestinal GVHD related to the HSCT, with children and adults, whose receiving oral or tube feeding nutrition therapy.

SELECTION CRITERIA

The study selection was based on the PRISMA method. Controlled clinical trials were searched. Randomization was not possible considering the rare condition.

DATA COLLECTION AND ANALYSIS

Two independent authors assessed the abstracts of the selected studies to determine the articles feasible to compose the review as the base to elaborate the practice guideline proposal protocol, object of the present study. To determine the level of evidence of the selected article, GRADE criteria were used.

MAIN RESULTS

One controlled clinical trial study was included. The study was developed in Japan with a total of 35 patients. The dietary plan was characterized by gradual increasing food consistency/density. They found better nutritional parameters in the treated group, however, following GRADE criteria, we rated the quality of evidence as very low.

AUTHORS' CONCLUSIONS

We could not demonstrate confidence in the effect estimate based on the selected study. However, considering the lack of literature information and the relevance of the topic, we decided to proceed and propose a practice guideline for an oral diet protocol for acute intestinal GVHD as a reference to be a starting point to validate protocols in future clinical trials. 2: Practice Guideline Proposal The criteria to elaborate the protocol were based on the RIGHT Statement. In addition to the literate information about diet and intestinal health, recommendations already adopted in the Service of Bone Marrow Transplant in the Complex Hospital of Clinics of Curitiba, in the state of Paraná, Brazil, were also considered.

Individuals, Boundaries, and Graft-versus-Host Disease

Hematopoietic cell transplantation generates new individuals, transplant chimeras, composed of 2 genetic partners-the patient and donor-derived cells-no longer restricted by their original genomes. Interactions of donor-derived and recipient cells occur prominently at the boundary of the recipient with a third partner, the microbiome, in particular skin and intestinal tract, leading to disruption of microbiome homeostasis. These interactions of donor and patient cells at the boundary set the stage for the development of graft-versus-host disease, an expression of the defense of individuality by recipient and donor. Establishment of tolerance and return of homeostasis at the boundary will allow for the survival of the new integrated, physiologic individual.

The gut microbiota in transplant patients

Solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients are at increased risk for developing infections due to underlying immunosuppression. Antibiotic use, and in HSCT recipients, the use of preparative regimens prior to transplantation can deplete gut commensal bacteria, resulting in intestinal dysbiosis. Emerging evidence in transplant patients, particularly HSCT, suggest that disturbances in gut microbiota populations are associated with a number of adverse outcomes. Here, we review the outcomes of HSCT and SOT recipients with gut microbiota imbalance or dysbiosis, explore the nascent field of gut microbiome therapeutic approaches including fecal microbiota transplantation and the use of precision probiotics in HSCT and SOT recipients.

An Essential Role of Innate Lymphoid Cells in the Pathophysiology of Graft-vs.-Host Disease

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is the only curative treatment for multiple hematologic malignancies and non-malignant hematological diseases. However, graft-vs.-host disease (GVHD), one of the main complications after allo-HSCT, remains the major reason for morbidity and non-relapse mortality. Emerging evidence has demonstrated that innate lymphoid cells (ILCs) play a non-redundant role in the pathophysiology of GVHD. In this review, we will summarize previously published data regarding the role of ILCs in the pathogenesis of GVHD.