Abstract: SA-PO211
A Case of Membranous Nephropathy Secondary to Chronic Lymphocytic Leukemia in Association with a Novel Antigen
Session Information
- Onconephrology: Immunological Cross-Talk
November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Radhakrishnan, Yeshwanter, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Sethi, Sanjeev, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Fervenza, Fernando C., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Zand, Ladan, Mayo Clinic Minnesota, Rochester, Minnesota, United States
Introduction
Membranous nephropathy (MN) is an uncommon presentation in patients with chronic lymphocytic leukemia (CLL). A novel target antigen has not been detected in MN associated with CLL. We describe a case of MN in association with CLL successfully treated with acalabrutinib and propose a novel antigen EGF-containing fibulin-like extracellular matrix protein (EFEMP2) as a possible target antigen in this disease.
Case Description
A 72-year-old male presented with bilateral lower extremity edema. His serum creatinine (Scr) was 1.7 mg/dL, serum albumin (SA) was 2.2 g/dL with 24-hour urine protein (24hUP) of 9g. Kidney biopsy revealed a PLA2R antibody negative and thrombospondin7A domain antibody negative MN with 1% of lymphocytic interstitial infiltrate consistent with CLL. He received rituximab (RTX) 1 g 2 doses 2 weeks apart. He went into partial remission with a 24hUP 1000 mg. He relapsed with reconstitution of B-cells due to which 2 additional RTX 1 g doses were given. However, he remained nephrotic despite RTX and a CD20+ B cell of 0. Subsequently, tacrolimus (TAC) 2 mg twice a day was initiated. He went into complete remission 1 year after TAC initiation but relapsed despite therapeutic levels of TAC. His 24hUP at the time of relapse was 13g with SA of 2.1 and Scr of 3.0. He received 2 doses of obinutuzumab 1 g 2 weeks apart for refractory MN. Despite that, he remained nephrotic over the next 4 months. He underwent a repeat kidney biopsy which demonstrated MN with 20% interstitial infiltrate that was PAX5, CD23, CD20 and CD5 stain positive consistent with clonal B-cell lymphoproliferation with features of CLL. Bone marrow (BM) biopsy showed CLL with 5-10% of the BM cellularity. CT chest and abdomen demonstrated widespread lymphadenopathy. Mass spectrometry of the first kidney biopsy showed moderate spectral count for EFEMP2 as the potential antigen in this case. He was initiated on Acalabrutinib 100 mg twice a day monotherapy. At last FU (12-month) he was in complete remission with Scr 2.4, 24hUP 370 mg and SA 4.5 without other therapies.
Discussion
Acalabrutinib monotherapy led to complete remission of MN with CLL. EFEMP2 is a possible target antigen in MN associated with CLL. Further studies are needed to confirm the presence of this antigen, disease association and outcomes in this patient cohort with MN and CLL.