Monoclonal gammopathy of undetermined significance does not affect outcomes in patients undergoing solid organ transplants

Background. Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic plasma cell proliferative disorder with a lifelong risk of progression to multiple myeloma or another plasma cell dyscrasia. Despite a high incidence in the general population and an increased relative risk for later malignancy, there are few reports about the clinical course of MGUS or risk profile in long-term immunosuppressed patients. Methods. We reviewed 1593 solid organ transplant patients and reported the frequency and outcomes of patients with MGUS identified pretransplant. Results. Polyclonal gammopathy pretransplant is common with 17% of all patients and as many as 75% of liver transplant candidates having increased globulins.However, a monoclonal immunoglobulin was identified in only 3% of all solid organ transplant patients pretransplant (n=34). Importantly, in these 34 patients, no cases of progression to multiple myeloma, amyloid, or lymphoma were observed during immune suppression, and there was no association between posttransplant lymphoproliferative disorders and pretransplant MGUS. Death in MGUS patients was not associated with progression of the monoclonal clone or development of posttransplant lymphoproliferative disorders or other malignancy. Conclusion. In conclusion, routine testing for MGUS before transplantation is not prognostic nor a contraindication to transplant, and therefore, it is not recommended.