| aHUS and organ transplantation |
| Posttransplant HUS is a rare but serious condition that can lead to poor patient and graft outcome |
| HUS can occur as a recurrence of aHUS after RT84 or as a de novo, potentially complement mediated, TMA in recipients of solid organ transplants85 as well as in recipients of hematopoietic stem cell transplantation86 |
| aHUS carries a risk of recurrence after RT. The risk is highest (up to 70%) in carriers of pathogenic variants in CFH, CFB, C3, or CFH/CFHR1 hybrid genes and in patients with a previous recurrence after RT.87 The lowest (<10%) risk is in patients with isolated MCP or DGKε variants and negative anti–factor H antibodies at the time of RT87 |
| The availability of the C5 blockers currently allows an individualized approach of RT in patients with aHUS. C5 blockade is frequently used for the prevention and/or early treatment of aHUS recurrence in patients at high risk. This strategy has greatly improved graft and patient outcome (<12% recurrence rate) and increased safe access to RT for patients with aHUS.84 An approach with living kidney donation (to reduce ischemia/reperfusion-triggered complement activation) without prophylactic C5 blockade has also been used with satisfactory results88 |
| Anti-C5 treatment is usually used lifelong after RT in patients with aHUS. However, case-by-case decisions can be made depending on the underlying genetic mutation |
| The difficulty remains in the differential diagnosis of aHUS, as in renal transplant recipients (and solid organ transplant recipients in general), TMA can be triggered by various events after transplantation: organ procurement (cold and warm ischemia/reperfusion injury), infection (in particular cytomegalovirus, influenza virus, parvovirus B19, and fungi), antiphospholipid antibodies, immunosuppressive drugs (calcineurin and mTOR inhibitors), and severe rejection episodes (in particular antibody-mediated rejection) |
| aHUS and organ transplantation |
| Posttransplant HUS is a rare but serious condition that can lead to poor patient and graft outcome |
| HUS can occur as a recurrence of aHUS after RT84 or as a de novo, potentially complement mediated, TMA in recipients of solid organ transplants85 as well as in recipients of hematopoietic stem cell transplantation86 |
| aHUS carries a risk of recurrence after RT. The risk is highest (up to 70%) in carriers of pathogenic variants in CFH, CFB, C3, or CFH/CFHR1 hybrid genes and in patients with a previous recurrence after RT.87 The lowest (<10%) risk is in patients with isolated MCP or DGKε variants and negative anti–factor H antibodies at the time of RT87 |
| The availability of the C5 blockers currently allows an individualized approach of RT in patients with aHUS. C5 blockade is frequently used for the prevention and/or early treatment of aHUS recurrence in patients at high risk. This strategy has greatly improved graft and patient outcome (<12% recurrence rate) and increased safe access to RT for patients with aHUS.84 An approach with living kidney donation (to reduce ischemia/reperfusion-triggered complement activation) without prophylactic C5 blockade has also been used with satisfactory results88 |
| Anti-C5 treatment is usually used lifelong after RT in patients with aHUS. However, case-by-case decisions can be made depending on the underlying genetic mutation |
| The difficulty remains in the differential diagnosis of aHUS, as in renal transplant recipients (and solid organ transplant recipients in general), TMA can be triggered by various events after transplantation: organ procurement (cold and warm ischemia/reperfusion injury), infection (in particular cytomegalovirus, influenza virus, parvovirus B19, and fungi), antiphospholipid antibodies, immunosuppressive drugs (calcineurin and mTOR inhibitors), and severe rejection episodes (in particular antibody-mediated rejection) |
RT, renal transplantation.