Long-Term Follow-Up of Patients with Monoclonal Gammopathy of Undetermined Significance after Kidney Transplantation

Abstract

Introduction: Long-term data regarding kidney transplantation (KTx) patients with monoclonal gammopathy of undetermined significance (MGUS) are scarce. We evaluated the long-term outcomes of these patients in a single-center retrospective study from the Mayo Clinic, Rochester, Minn., USA. Methods: Patients who had an MGUS before transplant or developed one after KTx were selected. Monoclonal protein was screened as part of the KTx evaluation by serum protein electrophoresis. Screening for posttransplant lymphoproliferative disorder (PTLD) or MGUS after transplant was not required by protocol. Patients with multiple myeloma, dysproteinemia-related kidney disease or no pretransplant serum protein electrophoresis were excluded. Results: Between 1963 and 2006, 3,518 patients underwent KTx. MGUS was identified in 42 patients, with 23 before transplant and 19 after transplant. Median follow-up for these patients was 8.5 years (range 0.3–37). Four (17.4%) pretransplant MGUS patients developed a hematologic malignancy: 2 smoldering multiple myeloma and 2 PTLD – an Epstein-Barr virus-positive diffuse large cell lymphoma and a Hodgkin lymphoma. None of the 19 patients who developed an MGUS after transplant progressed to multiple myeloma, but 2 (10.5%) developed Epstein-Barr virus-negative T cell lymphoproliferative disorders at 16 and 26 years after transplant. Median survival was 26.1 and 28.0 years for the pretransplant and posttransplant MGUS groups, respectively. Conclusion: Progression from true MGUS to multiple myeloma is rare after KTx. KTx appears safe in true MGUS patients if the monoclonal gammopathy was not the cause of the kidney disease. None of the patients progressed to multiple myeloma, but 2 developed smoldering multiple myeloma and several developed PTLD. Further studies are needed to explain the relationship between MGUS and PTLD.

Plasma Cell Neoplasms in US Solid Organ Transplant Recipients

“…In immunocompetent individuals, detection of an M-protein as an isolated finding (i.e., monoclonal gammopathy of undetermined significance [MGUS]) indicates the presence of an abnormal clone of plasma cells and is associated with the subsequent development of multiple myeloma (31). However, among transplant recipients, M-proteins are usually transient and not clearly predictive of development of PCNs or other forms of PTLD (28–30;32;33). …”

Kidney Disease and Multiple Myeloma

“…Recently, Naina et al (99) studied the outcomes of kidney transplant recipients and MGUS; 2 of 23 patients with pretransplant MGUS developed smoldering myeloma, and 2 patients developed another posttransplant lymphoproliferative disease over a mean follow-up of 8.5 years. None of the patients who developed MGUS post-transplant developed myeloma, but 2 patients developed post-transplant lymphoproliferative disease decades after transplantation (99).…”

Evaluation of Kidney Transplant Candidates: An Update in 2012

“…Specifically, EBV D+/R-when compared to D-/R-was associated with an increase in PTLD incidence of 35% and 42% in adult DD and LD renal transplants respectively [34]. A relationship between monoclonal gammopathy of undetermined significance (MGUS) and PTLD was observed in a recent single center retrospective study [35]. In the study, MGUS was defined as a serum M protein of less than 3.0 g/dL, bone marrow biopsy with less than 10% plasma cells, and the absence of end-organ involvement.…”

“…Of 42 patients with MGUS, 23 were identified prior to kidney transplant. After a median follow-up of 8.5 years, 4 (17.4%) patients with pretransplant MGUS went on to develop 2 cases each of smoldering multiple myeloma and PTLD [35]. Of the 19 posttransplant MGUS cases, none developed multiple myeloma but 2 patients were found to have EBV-negative T cell lymphoproliferative disorders at 16 and 26 years after transplant [35].…”

“…After a median follow-up of 8.5 years, 4 (17.4%) patients with pretransplant MGUS went on to develop 2 cases each of smoldering multiple myeloma and PTLD [35]. Of the 19 posttransplant MGUS cases, none developed multiple myeloma but 2 patients were found to have EBV-negative T cell lymphoproliferative disorders at 16 and 26 years after transplant [35]. The authors concluded that patients with MGUS, a common disease that occurs in 2% of the population under the age of 50 could safely receive a kidney transplant [35].…”