Immunosuppression Regimens for Intestinal Transplantation in Children

Update on Maintenance Immunosuppression in Intestinal Transplantation

Outcomes in intestinal transplantation remain hampered by higher rates of rejection than any other solid organs. However, maintenance immunosuppression regimens have largely remained unchanged despite advances in therapies for induction and treatment of rejection and graft-versus-host disease. Recently, there have been a small number of new maintenance therapies attempted, and older agents have been used in new ways to achieve better outcomes. The authors herein review the traditional maintenance therapies and their mechanisms and then consider updates in new therapies and new ways of using old therapies for maintenance immunosuppression after intestinal transplantation.

Immune reactions following intestinal transplantation: Mechanisms and prevention

For patients with intestinal failure, small bowel transplantation remains one of the most effective treatments despite continuous advancements in parenteral nutrition techniques. Long-term use of parenteral nutrition can result in serious complications that lead to metabolic dysfunction and organ failure. However, the small intestine is a highly immunogenic organ with a large amount of mucosa-associated lymphoid tissue and histocompatibility antigens; therefore, the small intestine is highly susceptible to severe immune rejection. This article discusses the mechanisms underlying immune rejection after small bowel transplantation and presents various options for prevention and treatment. Our findings offer new insights into the development of small bowel transplantation.

Biologicals in the prevention and treatment of intestinal graft rejection: The state of the art Biologicals in Intestinal Transplantation

Intestinal transplantation is the standard treatment for patients with intestinal failure with severe complications due to parenteral nutrition; however, rejection leads to graft failure in approximately half of both adult and pediatric recipients within 5 years of transplantation. Although intensive immunosuppressive therapy is used in an attempt to reduce this risk, commonly used treatment strategies are generally practice- and/or expert-based, as head-to-head comparisons are lacking. In this ever-developing field, biologicals designed to prevent or treat rejection are used increasingly, with both infliximab and vedolizumab showing potential in the treatment of acute cellular rejection in individual cases and in relatively small patient cohorts. To help advance progress in clinical care, we review the current use of biologicals in intestinal transplantation, and we provide future perspectives to guide this progress.

From intestinal failure to transplantation: Review on the current need for transplant indications under multidisciplinary transplant programs worldwide

INTRODUCTION

Intestinal failure, defined as the loss of gastrointestinal function to the point where nutrition cannot be maintained by enteral intake alone, presents numerous challenges in children, not least the timing of consideration of intestine transplantation.

OBJECTIVES

To describe the evolution of care of infants and children with intestinal failure including parenteral nutrition, intestine transplantation, and contemporary intestinal failure care.

METHODS

The review is based on the authors' experience supported by an in-depth review of the published literature.

RESULTS

The history of parenteral nutrition, including out-patient (home) administration, and intestine transplantation are reviewed along with the complications of intestinal failure that may become indications for consideration of intestine transplantation. Current management strategies for children with intestinal failure are discussed along with changes in need for intestine transplantation, recognizing the difficulty in generalizing recommendations due to the high level of heterogeneity of intestinal pathology and residual bowel anatomy and function.

DISCUSSION

Advances in the medical and surgical care of children with intestinal failure have resulted in improved transplant-free survival and a significant fall in demand for transplantation. Despite these improvements a number of children continue to fail rehabilitative care and require intestine transplantation as life-saving therapy or when the burden on ongoing parenteral nutrition becomes too great to bear.

Off-Label Immunosuppressant Drugs in Solid Organ Transplantation

Once a solid organ transplantation (SOT) has been performed, it is necessary to prescribe immunosuppressant medication to prevent graft rejection. This task has the peculiarity that many of these drugs do not have specific indications for transplant use in the technical data sheets. We performed a review of different immunosuppressive drugs' information available at European and American regulatory agencies in order to analyze the approved indications by the type of SOT. In our work, besides showing these differences between different indication approvals in different SOT modalities, we also attempted to reflect other differences under the approved indications according to age group, formulation type, geographical area, etc. Although consensus documents on the subject have been published, the access to immunosuppressants depends on each country's regulation and healthcare system, and off-label prescription is a reality that healthcare professionals need to be familiar with.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

Induction Versus Maintenance Immunosuppression After Intestinal Transplant: Determining Which Treatment Most Impacts Long-Term Patient And Graft Survival

OBJECTIVES

Immunosuppressive strategies for intestinal transplant have changed over time. However, specific intestinal transplant-oriented protocols and reports on long-term maintenance regimens are scarce. Our objective was to evaluate the impact of 2 different initial immunosuppressive protocols based on thymoglobulin (group A) and basiliximab (anti-interleukin 2 antibody) (group B) and of changes to maintenance immunosuppression over long-term follow-up in intestinal transplant recipients.

MATERIALS AND METHODS

We performed a retrospective analysis of a prospectively established protocol for intestinal transplant immunosuppression, conducted between May 2006 and December 2020. We analyzed 51 intestinal transplant recipients, with 6 patients excluded because of early death or graft loss. Acute cellular rejection frequency and grade, number of acute cellular rejection episodes, time to the first acute cellular rejection episode, response to treatment, number of patients who progressed to chronic allograft rejection, kidney function, infections, incidence of posttransplant lymphoproliferative disorder and graft-versus-host disease, and patient and graft survival were analyzed.

RESULTS

In the study groups, there were 87 acute cellular rejection episodes in 45 patients (33 in group A and 54 in group B). We found degree of acute cellular rejection to be mild in 45 patients, moderate in 18, and severe in 24 (not significant between groups). Our comparison of induction therapy (thymoglobulin [group A] vs interleukin 2 antibody [group B]) did not show any statistical difference during clinical followup. Long-term review showed that all patients were on tacrolimus. Five-year patient and graft survival rates were 62% and 45% for group A and 54% and 46% for group B, respectively (not significant).

CONCLUSIONS

Long-term patient and graft outcomes reflected the use of an individualized follow-up with adjustments and changes in immunosuppressive medications according to the patient's clinical course and complications rather than based on the induction immunosuppressive protocol used.