Improved outcome of renal transplantation in amyloidosis

[Hematologic malignant complications after transplantation]

Post-transplant hemopathies are a serious complication of organ transplantation. They include several entities: non-hodgkin lymphoma, Hodgkin disease and myeloma. The pathophysiology, clinical and histological features, treatment and evolution of these diseases are different, but share some similarities. Among factors involved in lymphomagenesis, the role of Epstein Barr virus and immunosuppression are central. EBV primo-infection or reactivation together with a deep depression of T-cell immunity is at particular risk of lymphoma development. The clinical expression and outcome of lymphomas are varied. Assays for EBV replication quantification have been developed leading to immunosuppression decreasing and antiviral therapy when the replication increases. Treatment of post-transplant lymphoproliferations consists mainly in immunotherapy and chemotherapy. Hodgkin disease and myeloma are rare after transplantation; their management is close to the one of immunocompetent patients. The recurrence of myeloma, amyloidosis or light chain deposition disease seems frequent after transplantation and only patients with disappearance of monoclonal component should be proposed for transplantation. On the opposite, the risk of recurrence appears lower for Hodgkin disease; therefore the transplantation of patients with a history of Hodgkin disease looks possible.

Recurrence of secondary glomerular disease after renal transplantation

The risk of a posttransplant recurrence of secondary glomerulonephritis (GN) is quite variable. Histologic recurrence is frequent in lupus nephritis, but the lesions are rarely severe and usually do not impair the long-term graft outcome. Patients with Henoch-Schonlein nephritis have graft survival similar to that of other renal diseases, although recurrent Henoch-Schonlein nephritis with extensive crescents has a poor prognosis. Amyloid light-chain amyloidosis recurs frequently in renal allografts but it rarely causes graft failure. Amyloidosis secondary to chronic inflammation may also recur, but this is extremely rare in patients with Behcet's disease or in those with familial Mediterranean fever, when the latter are treated with colchicine. Double organ transplantation (liver/kidney; heart/kidney), chemotherapy, and autologous stem cell transplantation may be considered in particular cases of amyloidosis, such as hereditary amyloidosis or multiple myeloma. There is little experience with renal transplantation in light-chain deposition disease, fibrillary/immunotactoid GN, or mixed cryoglobulinemic nephritis but successful cases have been reported. Diabetic nephropathy often recurs but usually only after many years. Recurrence in patients with small vessel vasculitis is unpredictable but can cause graft failure. However, in spite of recurrence, patient and graft survival rates are similar in patients with small vessel vasculitis compared with those with other renal diseases. Many secondary forms of GN no longer represent a potential contraindication to renal transplantation. The main issues in transplantation of patients with secondary GN are the infectious, cardiovascular, or hepatic complications associated with the original disease or its treatment.

Amyloidosis

Amyloidosis is a disease in which abnormal proteins form fibrillar tissue deposits that can compromise key viscera and lead to early death. In order to treat amyloidosis, the type of abnormal protein must be identified. The most common type is monoclonal immunoglobulin light chain or AL amyloidosis; the other important type is hereditary, caused by variant forms of transthyretin and other proteins, whereas amyloid associated with chronic inflammation ("secondary") is rare in the developed world. AL can be misdiagnosed if a monoclonal gammopathy and a hereditary variant are present in the same patient. The aim of therapy in systemic AL amyloidosis is to reduce the amyloid-forming monoclonal light chain, measured with the serum free light chain assay, by suppressing the underlying plasma cell dyscrasia, while using supportive measures to sustain organ function. Amyloid deposits can be resorbed and organ function restored if the amyloid-forming precursor light chain is eliminated. The most effective treatment for systemic AL amyloidosis is risk-adapted melphalan with peripheral blood stem cell transplant (SCT). The hematologic response rate is 75% at 12 months when adjuvant therapy with thalidomide and dexamethasone is used post-SCT. Patients can achieve long-term durable remissions with organ recovery. Drugs effective in multiple myeloma are usually helpful in AL amyloidosis if tolerated. The use of novel antibody-based approaches for imaging amyloid and possibly for accelerating removal of deposits is under active investigation.