We tested whether resetting the immune system with autologous HSC after preconditioning with Fludarabine improves kidney allograft survival in sensitized hosts.
Methods: MHC mismatched DA (RT1Aa) donors and Lewis (RT11) recipients were used. GFP transgenic Lewis (GFP+) rats were used as donors of syngeneic HSC. Lewis rats were presensitized to DA antigens with skin grafts. At 1 month after skin transplantation, sensitized Lewis rats were divided into three groups (table 1): l. sensitized controls; 2. preconditioned with lethally irradiation (12Gy) plus syngeneic HSCT (3×108 cells); and 3. fludarabine pretreatment (25mg/kg/day, i.p. for 1 wk) followed by preconditioning with lethally irradiation plus syngeneic HSCT. At 2 month after HSCT, Lewis rats received DA kidneys after nephrectomy. Recipient rats were treated with tacrolimus (1mg/kg/d for 1wk, 0.5mg/kg/d for 1wk, and 0.1mg/kg/d for 1wk) after kidney transplantation. Serum DSA levels, GFP+ blood cells and memory B cells (CD45RA+CD27+) were analyzed by flow cytometry. DSA production in cultured splenocytes was also determined before and after HSCT.
Results: All group 1 rats died within 10 days after kidney allotransplantation. Group 2 rats given lethal irradiation plus GFP+ HSCT had repopulation of blood, spleen, thymus and lymph nodes by GFP+ cells. Serum DSA levels were reduced 60-70% and DSA production in cultured splenocytes was also significantly decreased. However, despite these findings suggesting benefit all grafts were lost by day 25. Of interest, a week of fludarabine treatment preceding HSCT enabled both DSA reduction and long-term survival of 5 out of 6 rat kidney allografts in sensitized hosts.
|1||DA||Lew||DA Skin||No||No||DA Kidney||3,4,6,8,8,10|
|2||DA||Lew||DA Skin||No||Lew HSC (GFP+)||DA Kidney||8,17,23,25|
|3||DA||Lew||DA Skin||25mg/kg/d, i.p., 1wk||Lew HSC (GFP+)||DA Kidney||11, >27, >47, >49, >60, >90|
Conclusion: Fludarabine treatment which is thought to deplete B cells may be necessary to control anamnestic responses before re-setting the immune system with HSCT. These results suggest that autologous HSCT coupled with fludarabine and total body irradiation may provide a new approach enabling the successful transplantation of highly sensitized patients.
To cite this abstract in AMA style:Fu Y, Montgomery R, Wang Y, Fuchs E, Shen Z, Williams G, Sun Z. Successful Transplantation of Kidney Allografts in Sensitized Rats Made Possible by Autologous Hematopoietic Stem Cell Transplantation (HSCT) and Fludarabine [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/successful-transplantation-of-kidney-allografts-in-sensitized-rats-made-possible-by-autologous-hematopoietic-stem-cell-transplantation-hsct-and-fludarabine/. Accessed November 24, 2020.
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