Date: Monday, June 3, 2019
Session Time: 6:00pm-7:00pm
Presentation Time: 6:00pm-7:00pm
Location: Hall C & D
*Purpose: Monoclonal (M)Ig-associated renal disease comprises a group of disorders caused by paraproteins. Little is known about this entity in the renal allograft, as it is rarely encountered and poorly studied.
*Methods: We retrospectively searched our archives for renal allograft biopsies diagnosed with MIg-associated renal disease from 2007-2018.
*Results: The cohort included 26 patients with the following diagnoses: AL amyloidosis (n=5), light chain deposition disease (n=5), light chain proximal tubulopathy (n=2), light chain cast nephropathy (n=1), and proliferative glomerulonephritis with MIg deposits (PGNMID) (n=13). Patients were 54 ± 16 years old and included 31% women and 16% black race. MIg-associated renal disease accounted for 9 (35%) of ESRD etiologies in the native kidney while the others were presumed to have manifested de novo. The disease occurred on average 5.4 ± 5.4 years after transplantation. Thirteen (50%) patients had hematologic disorders: 7 multiple myeloma, 1 non-Hodgkin lymphoma, and 5 plasma cell neoplasm (bone marrow cellularity <10%). In 8 (62%) of these 13 patients, the allograft biopsy diagnosis triggered a hematologic workup and the new detection of hematologic disorder.
Patients with PGNMID (n=13) were compared to the group with all other MIg-related conditions combined (n=13). While graft survival was similar, PGNMID patients had lower frequency of detectable M-spike in the serum or urine [3/13 (23%) vs 12/13 (92%) P=0.001] and overt hematologic disorder [3/13 (23%) vs 10/13 (77%) P=0.02]. Allograft biopsies of all 3 PGNMID patients with hematologic disorders demonstrated organized deposits [2 fibrils; 1 lattice-like vs. 0 other PGNMID] and none had IgG3 staining (vs 40% in other PGNMID). In 6/13 (46%) patients with PGNMID, the clonality of the deposits changed from monoclonal to polyclonal or vice versa between native kidney and allograft (n=3) or on serial allograft biopsies (n=3).
*Conclusions: In conclusion, post-kidney transplant PGNMID often lacks an identifiable hematologic disorder, especially in cases with IgG3, undetectable M-spike, and no deposit substructure. In such cases, careful follow-up by serial serum and urine immunofixation may be sufficient. In contrast, a thorough hematologic workup is needed in other forms of MIg-associated renal disease.
To cite this abstract in AMA style:Kamal J, Crew RJ, Ye X, Swanson J, Appel G, Markowitz G, D'Agati V, Batal I. Clinicopathologic Assessment of Monoclonal Immunoglobulin (Ig) Associated Renal Disease in the Kidney Allograft [abstract]. Am J Transplant. 2019; 19 (suppl 3). https://atcmeetingabstracts.com/abstract/clinicopathologic-assessment-of-monoclonal-immunoglobulin-ig-associated-renal-disease-in-the-kidney-allograft/. Accessed October 24, 2020.
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