Complications after kidney transplantation

Kidney transplantation enables patients with end-stage kidney failure to regain kidney function and achieve a better quality of life. However, it requires long-term medical follow-up to preserve the function of the transplanted kidney and prevent or treat complications that may occur after transplantation.

These complications may be related to the immune system, immunosuppressive treatments, infections, cardiovascular disease or the underlying kidney disease. Some complications may occur soon after transplantation, while others appear several years later.

Specialised care makes it possible to detect abnormalities promptly, investigate their cause and adjust treatment in order to preserve the graft and the patient’s overall health.

Complications after kidney transplantation include, in particular:

• Acute or chronic rejection of the transplanted kidney;
• Infections, particularly opportunistic infections related to immunosuppression;
• Viral infections such as CMV or BK virus;
• Complications related to immunosuppressive medicines;
• Recurrence of the initial kidney disease in the graft;
• Cardiovascular and metabolic complications;
• High blood pressure, diabetes and lipid disorders;
• Haematological and bone complications;
• Cancers promoted by immunosuppression;
• Urological or surgical complications affecting the graft;
• Progressive deterioration of graft function, which may, in some cases, lead to transplant loss.

The management of transplant patients therefore relies on a balance between sufficient immunosuppression to prevent rejection and limited immunosuppression to reduce the risk of infections, cancers and other complications.

Specialist assessment is necessary, in particular in the event of:

• Increased creatinine levels or an unexplained decrease in graft function;
• New or increased proteinuria;
• Fever or signs of infection;
• Urinary symptoms or decreased urine output;
• Unexplained increase in blood pressure;
• Persistent digestive problems that may affect the absorption of medications;
• Adverse effects or suspected toxicity of immunosuppressive medications;
• Abnormal blood levels of anti-rejection medications;
• Detection of a viral infection such as CMV or BK virus;
• Appearance of a mass, skin lesion or other symptoms that may suggest a tumour-related complication.

A change in the function of the transplanted kidney does not necessarily mean that rejection is occurring. Prompt investigation makes it possible to distinguish between the different possible causes and adjust the treatment.

Diagnosis is based on regular monitoring and a specialised assessment of the graft function.

Depending on the situation, the examinations may include:

• A blood test to assess kidney function;
• Testing for and quantification of proteinuria;
• Measurement of immunosuppressive drug levels;
• Testing for viral infections, particularly CMV and BK virus;
• An ultrasound scan of the graft and other imaging examinations;
• Testing for donor-specific antibodies (DSA);
• A biopsy of the transplanted kidney when necessary;
• Specialised microbiological, immunological or genetic tests, depending on the context.

A graft biopsy can, in particular, help distinguish rejection from other causes of transplant dysfunction and guide treatment.

The management of complications following kidney transplantation at H.U.B. is based on close collaboration between the nephrology and transplantation teams and the various specialties required for patient follow-up.

Nephrology and transplantation expertise

Nephrologists provide long-term follow-up for transplant patients, monitor graft function and adjust immunosuppressive treatment.

In the event of graft dysfunction, a rapid assessment is carried out to investigate the various possible causes, including rejection, infection, drug toxicity, recurrence of the original kidney disease or a urological complication.

Multidisciplinary care

Depending on the clinical situation, various specialists may be involved:

• Nephrology;
• Kidney transplantation team;
• Urological surgery;
• Infectious diseases;
• Immunology;
• Anatomical pathology;
• Radiology;
• Cardiology;
• Endocrinology;
• Haematology;
• Oncology;
• Dermatology;
• Medical genetics.

This multidisciplinary approach ensures comprehensive management of complications that may occur in transplant patients.

Rejection of the transplanted kidney

Rejection is an immune system reaction by the patient against the transplanted kidney. It may occur early or several years after transplantation.

There are different mechanisms of rejection, and distinguishing between them is essential for selecting the appropriate treatment.

Diagnosis is based on analysis of kidney function, testing for donor-specific antibodies, immunological assessment and, where indicated, a graft biopsy.

Prompt management is essential to limit graft damage and preserve its function.

Infections and complications related to immunosuppression

Immunosuppressive medicines reduce the immune response to prevent rejection, but they also increase the risk of infections.

Specific monitoring is organised to detect certain viral infections, particularly CMV and BK virus, at an early stage. Early detection of BK virus replication makes it possible, in particular, to adjust immunosuppression and reduce the risk of graft involvement.

Bacterial, viral, fungal or opportunistic infections may also require specialist management in collaboration with infectious disease specialists.

Long-term complications

Follow-up of transplant patients is not limited to monitoring the graft.

Immunosuppression and chronic kidney disease may promote certain long-term complications, including cardiovascular diseases, metabolic disorders, bone complications and certain cancers.

Preventive care is therefore put in place to reduce these risks and improve patient and graft survival.

Recurrence of kidney disease in the graft

Some kidney diseases may recur after transplantation and lead to a gradual decline in graft function.

The risk of recurrence depends on the original kidney disease. Specific monitoring is organised for patients with a disease that may recur, allowing early diagnosis and appropriate management.

Research and innovation at H.U.B.

H.U.B. actively contributes to advancing knowledge in the field of kidney transplantation and its complications.

The teams are involved in clinical and translational research projects focusing in particular on the mechanisms of rejection, the immune response, infections after transplantation and complications related to immunosuppressive treatments.

This work helps improve understanding of post-transplantation complications and develop new diagnostic and therapeutic strategies.

Paediatric–adult collaboration and transition

Kidney transplantation can be performed in children and adolescents. Follow-up must then take into account specific issues relating to growth, development, schooling and the gradual acquisition of independence.

Within H.U.B., the paediatric nephrology teams at the Queen Fabiola Children’s University Hospital (HUDERF) and the adult nephrology team at Erasme Hospital collaborate to ensure continuity of care.

A transition pathway is organised for adolescents and young adults to gradually prepare them for transfer to adult teams, while maintaining appropriate monitoring of the graft and immunosuppressive treatment.

This organisation ensures continuity of care and limits interruptions in follow-up during a particularly important period in the life of a transplant patient.

• Specialised expertise in renal transplantation and long-term follow-up of transplant recipients;
• Management of common, rare and complex complications;
• Access to multidisciplinary expertise;
• Close collaboration between nephrology, transplantation, surgery and other specialties;
• Access to specialised immunological, virological, radiological and histopathological examinations;
• Management of rejection and complex graft dysfunction;
• Expertise in managing infections and complications related to immunosuppression;
• Management of patients experiencing recurrence of their kidney disease in the graft;
• Close collaboration between paediatric and adult nephrology;
• Organisation of the paediatric-to-adult transition pathway;
• Participation in clinical and translational research projects.