Clinical Patterns and Outcomes of AL Amyloid Recurrence After Kidney Transplant

Background: Prior studies have shown that AL amyloidosis patients can successfully undergo kidney transplantation with good outcomes. This study examines hematologic, renal characteristics of AL amyloidosis recurrence - crucial insights for optimal outcomes in this challenging patient population. Methods: This retrospective cohort study evaluated 66 patients with AL amyloidosis that underwent kidney transplant from 1999 to 2018 at Mayo Clinic Rochester. Linear regression, ROC curve analysis and Kaplan-Meier method were used. Results: With a median follow-up of 62 months, 26 of the 66 patients had AL amyloid recurrence post-transplant. Recurrences were detected by protocol biopsy in 30.8% of patients. Patients with lambda light chain (LC) AL amyloidosis have a higher risk of recurrence versus kappa LC (51% vs 22%), and complete hematologic response (CR) was associated with a longer time to recurrence (128 vs 62 months). A dFLC ≥1.85 was predictive for recurrent amyloid (OR 13.3, 95% CI 3.48-68.2). There was no association between the last hematologic treatment and time to recurrence. Conclusion: Our results show that lambda iFLC, non-CR response and dFLC ≥1.85 are associated with a higher risk of AL amyloidosis recurrence post-renal transplant.A) Higher recurrence risk with lambda iFLC B) Longer time to recurrence in CR vs VGPR C) dFLC >1.85 predictive of recurrence, independent of iFLC D) Box plot of dFLC levels pre-, post-, and at recurrence Baseline Characteristics - Baseline characteristics Total (n=66) No recurrence(n=40) Recurrence(n=26) P-value Age at kidney transplant (years) 58 ± 8.4 59.1 ± 7.2 56.3 ± 10 0.2 Male sex, n (%) 42 (63.6) 26 (65) 16 (61.5) 0.8 Lambda free light chain involves, n (%) 39 (59.1) 19 (47.5) 20 (76.9) 0.02 Best hematologic response prior kidney transplant, n (%)- CR- VGPR- PR- NR- Treatment-naive 35 (53)15 (22.7)6 (9.1)2 (3)8 (12.1) 26 (65)7 (17.5)1 (2.5)1 (2.5)5 (12.5) 9 (34.6)8 (30.8)5 (19.2)1 (3.8)3 (11.5) 0.04 Induction for Kidney Transplant- No induction - ATG - Basiliximab - Daclizumab - Alemtuzumab 3 (4.8) 21 (33.3) 33 (52.4) 1 (2.6) 5 (7.9) 2 (5.1) 16 (41) 18 (46.2) 1 (1.6) 2 (5.1) 1 (4.2) 5 (20.8) 15 (62.5) 0 3 (12.5) 0.375 Clinical presentation at recurrence, n (%)- Protocol Biopsy- Rising serum creatinine*- New onset proteinuria**- Rising serum creatinine AND new proteinuria n/a n/a 8 (30.8)12 (46.2)4 (15.4)2 (7.7) n/a Serum creatinine, mg/dL (IQR) n/a 1.6 (1.3-2) 1.6 (1.1-2) 0.74 24-hour urine protein, g (IQR) n/a 0.2 (0.1-0.3) 0.3 (0.1-0.7) 0.05 Protocol Biopsy (no aberrant serum or urine biomarkers); *Cr≥0.3 mg/dL; **Urine protein≥0.5 g above post-transplant nadir or ≥1g/24 hr