Rituximab (RIT), anti-CD20 antibody, has been applied to kidney transplantation because of its potent B-cell depleting effect. Although CD20+ cells in peripheral blood (PB) and spleen are consistently depleted in patients receiving RIT, the clinical effects are heterogeneous, probably related to differences in the depleting effects of secondary lymphoid organs (SLOs), such as peripheral lymph nodes (LNs). The aim of this study was to investigate surviving B cells in different compartments (PB, spleen, and LN) after administration of RIT and its association with clinical outcomes.
Since April 2005, 43 patients with immunological high risks [ABO-incompatible (ABOI) or donor specific antibody (DSA) positive or both] received a single dose of RIT with 200 mg/body at 1 or 3 weeks before kidney transplantation. They received 3 to 4 sessions of apheresis prior to transplantation. The induction immunosuppressive therapy was consisted of tacrolimus, MMF, steroid, and basiliximab. In all patients, the several pelvic LNs were dissected at the time of transplantation. Of those, 2 ABOI and 6 DSA positive patients received splenectomy concurrently with transplantation. Immunohistochemical intensity of B cell subsets (CD20, CD27, CD79a, and CD138) in LN and spleen was scored and compared to the controls comprised recipients undergoing lymph node dissection (n=9; ABO-compatible) and splenectomy (n=4; ABOI) without RIT. Then, we investigated the clinical significance.
CD20+ cells in PB and spleen were remarkably depleted by RIT. The intensity scores of CD20 and CD79a in LNs were significantly lower in the recipients with RIT compared to those without (p < 0.001, respectively). However, CD20+ cells were considerably less susceptible to RIT in LNs than in PB and spleen. Acute antibody-mediated rejections (AAMR) (8/43, 19%) or opportunistic infections (19/43, 44%) were not associated with the intensity score in LNs. The occurrence of AAMR was associated with the existence of DSA before transplant only.
Although CD20+ cells in PB and spleen were depleted by RIT, the immunohistochemical intensity of B cell subsets in LNs were less susceptible and not association with clinical outcomes. A 200 mg/body of RIT may not completely deplete the persistence B or memory B cells in LNs resulting in the occurrence of AAMR due to DSA, but not ABOI.
To cite this abstract in AMA style:Saito M, Satoh S, Numakura K, Inoue T, Tsuruta H, Akihama S, Narita S, Tsuchiya N, Habuchi T. Surviving B Cells in Different Lymphoid Organs after Rituximab Administration and Its Association with Clinical Outcomes [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/surviving-b-cells-in-different-lymphoid-organs-after-rituximab-administration-and-its-association-with-clinical-outcomes/. Accessed November 23, 2020.
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