Abstract: SA-PO1029
Renal Whodunit: The Paraprotein Connection
Session Information
- Transplantation: Clinical - 4
October 26, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2102 Transplantation: Clinical
Authors
- Boldridge, Jessica, Brown University, Providence, Rhode Island, United States
- Bayliss, George P., Brown University, Providence, Rhode Island, United States
- Chang, Anthony, University of Chicago Division of the Biological Sciences, Chicago, Illinois, United States
Introduction
A monoclonal gammopathy is an abnormal increase in the synthesis of one of the five immunoglobulin (Ig) isotypes. These monoclonal Igs are also referred to as paraproteins which can be nephrotoxic. Manifestations can range from tubulopathies to glomerular disease. Known paraprotein diseases include multiple myeloma, Waldenstrom macroglobulinemia, CLL and malignant lymphoma. All other B cell lymphoproliferative and plasma cell proliferative disorders that result in kidney disease are referred to as monoclonal gammopathy of renal significance.
Case Description
A 68 yo male with a PMH of ESRD secondary to FSGS status post (s/p) living donor kidney transplant in 2020 who was admitted to the hospital for acute kidney injury (AKI). Six weeks prior to presentation, he was diagnosed with IgM paraprotein associated with a low-grade lymphoproliferative disorder most consistent with CD5 positive marginal zone lymphoma. Per hematology/oncology, the initial plan was to not treat unless the patient had systemic involvement. There was no known systemic involvement at that time. Fast forward six weeks and labs are now significant for a creatinine (Cr) of 3.2 mg/dL. Urinalysis positive for 1+ for blood, 30 protein. Tacrolimus level was 6.7. He tested covid positive. Biopsy was pursued which showed no signs of rejection but acute tubular necrosis and ongoing ischemic changes possibly related to tacrolimus. Four of 24 glomeruli were globally sclerosed. There was also severe hyalinosis and moderate IFTA 30%. The plan at that time was to start belatacept and to titrate down tacrolimus. Routinely, immunofluorescence (IF) is not obtained on transplant biopsies. Given new onset AKI and recently diagnosed malignancy, pathology was asked to review the allograft biopsy samples. IF showed evidence of light chain cast nephropathy, kappa light chain restricted.
Discussion
We present a rare case of a light chain cast nephropathy in a renal allograft. As described in this case, the preliminary plan was to hold treatment as he had no known systemic manifestations. The plan changed once AKI developed. Initial result of the biopsy was suggestive of tacrolimus toxicity with plans to alter immunosuppression accordingly. Maintaining monoclonal gammopathy of the allograft as a differential diagnosis is essential in relevant patients as it can alter treatment and important to remain as a differential for all learners.