From the Guidelines
Risk factors for intestinal transplant rejection include immunological factors, technical complications, patient-related factors, medication non-adherence, and infections, with the most recent and highest quality study suggesting that immunosuppression regimens combining tacrolimus, corticosteroids, and antimetabolites like mycophenolate mofetil are effective in preventing rejection 1.
Key Risk Factors
- Immunological factors: HLA mismatching between donor and recipient, pre-existing donor-specific antibodies, and previous sensitization through blood transfusions or pregnancies
- Technical complications: prolonged cold ischemia time (over 9 hours) and surgical complications
- Patient-related factors: younger recipient age, certain underlying diseases like inflammatory bowel disease, and poor nutritional status pre-transplant
- Medication non-adherence: inconsistent immunosuppressive therapy allows the immune system to mount a response against the graft
- Infections: particularly cytomegalovirus (CMV) and Epstein-Barr virus (EBV), can trigger inflammatory responses that promote rejection
Post-Transplant Monitoring and Immunosuppression
- Frequent endoscopies with biopsies are necessary for monitoring rejection
- Immunosuppression regimens usually combine tacrolimus, corticosteroids, and antimetabolites like mycophenolate mofetil, with careful therapeutic drug monitoring to maintain appropriate levels 1
- The introduction of novel immunosuppressive protocols has improved outcomes in intestinal transplantation, with a current 1-year patient survival rate of 92% and a graft survival rate of 89% 1
Important Considerations
- The intestine's high immunogenicity due to its large lymphoid tissue content and constant exposure to environmental antigens makes it particularly susceptible to rejection compared to other solid organs
- Infections, particularly CMV and EBV, can resemble rejection clinically and histologically, and therefore require careful diagnosis and management 1
From the Research
Risk Factors for Intestinal Transplant Rejection
The risk factors for intestinal transplant rejection can be categorized into several key areas, including:
- Patient characteristics: age, underlying medical conditions, and immunosuppression regimen 2
- Transplant characteristics: type of transplant (e.g. intestinal only vs. multivisceral), inclusion of other organs (e.g. liver), and donor-recipient matching 3, 4
- Immunological factors: presence of anti-HLA donor specific antibodies (DSA) and calculated panel reactive antibody (cPRA) levels 5
Patient-Related Risk Factors
Some patient-related risk factors for intestinal transplant rejection include:
- Age: children under 18 years old have a higher incidence of bloodstream infections, which may increase the risk of rejection 3
- Underlying medical conditions: patients with Crohn's disease may have a higher risk of graft failure compared to those without Crohn's disease 4
- Immunosuppression regimen: tacrolimus time-in-therapeutic range (TAC-TTR) is associated with freedom from acute rejection and graft failure, with lower TAC-TTR increasing the risk of rejection and graft loss 2
Transplant-Related Risk Factors
Transplant-related risk factors for rejection include:
- Type of transplant: inclusion of the liver in the transplant may increase the incidence of bloodstream infections, which may increase the risk of rejection 3
- Donor-recipient matching: higher number of HLA mismatches may increase the risk of rejection 6
Immunological Risk Factors
Immunological risk factors for rejection include: