De novo Light Chain Deposition Disease in a Kidney Allograft: A Case Report and Literature Review

Light chain deposition disease (LCDD) is a rare entity that can occur with and without an associated hematological malignancy, involves the deposition of clonal light chains in the kidney, and can often progress to end-stage kidney disease. Managing LCDD involves treatment to eliminate the underlying clone, which can recur in the transplanted kidney. Very few cases of de novo LCDD have been described in a kidney allograft; and most of them have occurred with an associated malignancy. They have also had variable outcomes as their management can be extremely challenging to mitigate infection risk and avoid rejection. We report a de novo case of LCDD occurring in a renal allograft without an associated hematological malignancy that presented with rapidly progressive acute kidney injury and crescentic glomerulonephritis on the kidney biopsy. Early initiation of chemotherapy using bortezomib, cyclophosphamide and dexatmethasone with minimal adjustment of the immunosuppressive therapy mostly preserved kidney function. De novo LCDD disease after renal transplantation can be challenging to suspect, especially in the absence of signs of hematologic malignancy. An early kidney biopsy is beneficial for diagnosis with light chain restriction using fluorescent immunostaining, even if there is no M-protein present and the mode of presentation is crescentic glomerulonephritis, which is atypical LCDD.