Abstract: SA-PO1133
Donor Derived Cell-Free DNA Positivity: Does It Always Denote Allograft Rejection?
Session Information
- Transplant Trainee Case Reports
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Report
- 1902 Transplantation: Clinical
Authors
- Sambharia, Meenakshi, Allegheny General Hospital, Pittsburgh, Pennsylvania, United States
- Sureshkumar, Kalathil K., Allegheny General Hospital, Pittsburgh, Pennsylvania, United States
- Zahid, Sohaib, Allegheny General Hospital, Pittsburgh, Pennsylvania, United States
- Chopra, Bhavna, Allegheny General Hospital, Pittsburgh, Pennsylvania, United States
Introduction
Donor derived cell free DNA (dd-cfDNA) is a novel serum biomarker now available to predict acute rejection in renal allografts. Presence of dd-cfDNA > 1% suggests allograft injury; caused by acute rejection. We describe a rare form of post-transplant lymphoproliferative disorder (PTLD) presenting as positive dd-cfDNA.
Case Description
A 64 yo white male who underwent living related kidney transplant 3 years earlier with baseline serum creatinine(Cr) around 1.5 mg/dl presented with worsening allograft function. Serum Cr was 9mg/dl with 4.5 grams/day proteinuria. Elevated dd-cfDNA level at 2.5% prompted a renal allograft biopsy.Light microscopy showed mild mesangial matrix expansion, Immunofluorescence showed 3+ deposition of lambda light chain in a linear pattern along glomerular and tubular basement membrane suggestive of lambda light chain deposition disease(LCDD)-refer to figure 1.
A subsequent bone marrow biopsy was consistent with lamda light chain restricted plasma cell dyscrasia. Patient was started on chemotherapy with cyclophosphamide, bortezomib, and dexamethasone along with plasmapheresis. Within a month, his renal allograft function improved with Cr of 1.6 mg/dl. After 6 months, he underwent autologous stem cell transplant(SCT)and currently remains in remission on Ixazomib. Repeat bone marrow biopsy and kidney biopsy have been normal.Cr remains at 1.3-1.5mg/dl one year post SCT. Repeat dd-cfdna levels remained <1%.
Discussion
This is the first reported case of lambda restriced LCDD, a rare form of PTLD in renal allograft presenting as positive dd-cfDNA. Elevated dd-cfDNA in our patient likely reflects allograft injury resulting from parenchymal infiltration with neoplastic cells along with light chain depostion.Our case highlights the need to include unusual causes of allograft injury in the differential diagnosis in patients presenting with renal allograft dysfunction and elevated dd-cfDNA. Allograft biopsy remains the gold standard in reaching a definite diagnosis.