Current opinions in nephrology and hypertension: kidney transplantation in patients with plasma cell dyscrasias

Diagnosis and management of monoclonal gammopathy of renal significance: A British Society for Haematology good practice paper

This guideline provides consensus opinion on the investigations required for people presenting with suspected monoclonal gammopathy of renal significance to both nephrology and haematology physicians. The guideline discusses the principles of treating a patient with MGRS and provides recommendations for both supportive management and haematological therapy. It details the recommended on-going monitoring required for both specialty areas.

Kidney Transplantation in Patients With Monoclonal Gammopathy of Renal Significance

Monoclonal gammopathy of renal significance (MGRS) defines disorders characterized by direct or indirect kidney injury caused by a monoclonal immunoglobulin produced by a B-cell or plasma-cell clone that does not meet current hematologic criteria for therapy. MGRS-associated kidney diseases are diverse and can result in the development of end-stage kidney disease. The current paradigm states that the underlying hematologic condition should be treated and in deep remission before kidney transplantation can be performed because recurrence has been reported for all MGRS-associated kidney diseases. However, we suggest that decisions regarding kidney transplantation in MGRS patients should be individualized considering many factors such as the subtype of MGRS-associated kidney disease, patient age and comorbidity, presence and risk of extrarenal complications, estimated waiting time, the availability of a living kidney donor, and previous hematological treatment and response. Thus, kidney transplantation should be considered even in treatment-naive patients, with hematological treatment initiated after successful kidney transplantation.

Kidney Transplantation and Monoclonal Gammopathy of Undetermined Significance

Plasma cell disorders are one of the most common hematologic malignancies. Monoclonal gammopathy of undetermined significance (MGUS) is defined by a serum monoclonal protein <3 g/dL, bone marrow plasma cell infiltration <10%, and most importantly absence of end-organ damage. The prevalence of MGUS in general population is estimated to be 1%–4% and its frequency increases with age with 3% among people above 50 y of age. The risk of progression to clinically significant plasma cell dyscrasia is estimated to be 1% per year. With aging population and increasing use of transplantation for the management of kidney disease in older adults, MGUS is being identified during the evaluation for kidney transplant candidacy or during the postkidney transplant follow-up. MGUS in patients with end-stage renal disease (ESRD) undergoing evaluation for kidney transplant can pose a complex management dilemma. In this article, we review the current state of knowledge about the prevalence of MGUS in ESRD population and the impact of kidney transplantation on the progression of MGUS to clinically significant plasma cell disorder. We make recommendations for the screening of ESRD patients undergoing kidney transplant evaluation and the management of MGUS after renal transplant.

Monoclonal Gammopathies After Renal Transplantation: A Single-center Study

INTRODUCTION

Plasma cell disorders (PCDs) are clonal plasma cell disorders that include conditions such as monoclonal gammopathy of undetermined significance (MGUS), monoclonal gammopathy of renal significance (MGRS), multiple myeloma (MM), smoldering MM (SMM), solitary plasmacytoma, and light-chain (AL) amyloidosis. The risk factors associated with and the clinical course of PCDs after renal transplantation is not well established although immunosuppressive protocols may impact the incidence and natural history of PCDs posttransplant.

PATIENTS AND METHODS

This single-center retrospective study evaluated patients with a history of renal transplant who developed a PCD between January 1, 2014-December 31, 2018.

RESULT

A total of 41 patients met the inclusion criteria including 29 with MGUS and 12 with symptomatic PCD (4 with MM, 2 with SMM, 4 with MGRS, 1 with AL amyloidosis, and 1 with solitary plasmacytoma). The median follow-up of survivors was 41.6 months. Three patients (1 with MGUS and 2 with MGRS) progressed to MM during the follow-up period. There was a male preponderance in both groups. There was no correlation between the donor and immunosuppressive regimen and the development of a PCD. Patients with symptomatic PCD had higher serum creatinine and M-protein levels at diagnosis and higher free light chain ratio and plasma cell burden. There was also a higher percentage of allograft failure noted in the symptomatic PCD subset 50% (n = 6), whereas only 23% (n = 7) of patients had allograft failure in the MGUS group.

CONCLUSION

This study shows the importance of considering monoclonal gammopathy in the differential of renal dysfunction after kidney transplant and the need to follow these patients closely to monitor for progression to symptomatic PCD.