*Purpose: Deceased donor solid organ transplant in sensitized recipients with donor specific antibodies (DSA) and positive flow cytometry cross matches (FXM) are challenging due to insufficient time for pre-transplant immunomodulatory therapies. In this study, sensitized kidney/pancreas recipients received a temporary splenic transplant under the hypothesis that spleen would allow efficient clearance of DSA in a limited time span therefore providing a safe immunologic window for transplant.

*Methods: Pancreas transplantation was performed with spleen preserved (not removed during the backbench); the spleen is left in place for 2 hours, removed just before the reperfusion of the kidney and sent to pathology. Once the spleen is removed, a repeat FXM and DSA are tested. Seven sensitized recipients received a temporary donor splenic transplant. Pre-splenic and post-splenic transplant FXM and DSA analyses were performed.

*Results: Three sensitized recipients were both T-cell and B-cell FXM positive; 2 were only B-cell FXM positive. Post-splenic transplant, all became FXM negative. Pre-transplant, Class I DSA were detected in 6 recipients and Class II DSA in 4 recipients. Post-splenic transplant, Class I DSA were not detected while Class II DSA persisted in 3 of the 4 recipients; all showed a marked decrease in DSA MFI. The histology of the explanted spleen showed marked neutrophilic and macrophage infiltration in the sinusoids, numerous neutrophilic microabscesses, and focal capillaritis. The C4d and IgG immunohistochemical stains were diffusely positive in the endothelial lining of the capillaries and sinusoidal lining, indicating diffuse IgG deposition and complement activation.

*Conclusions: Donor spleen seems to be an efficient strategy in sequestering DSA on splenic nucleated cells and antigen presenting cells. This could provide an immunologically safe window for transplantation of the kidney graft.

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