Volume 84, Issue 4, Pages 722-732 (October 2013) Sequential analysis of donor-specific antibodies and pathological findings in acute antibody-mediated rejection in a rat renal transplantation model  Naoki Kohei, Tatsu Tanabe, Shigeru Horita, Kazuya Omoto, Hideki Ishida, Yutaka Yamaguchi, Kazunari Tanabe  Kidney International  Volume 84, Issue 4, Pages 722-732 (October 2013) DOI: 10.1038/ki.2013.117 Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 1 Sequential analysis of donor-specific antibodies (DSAs)—immunoglobulins G and M (IgG and IgM). Change in molecules of equivalent soluble fluorochrome (MESF) values (a) after skin transplantation (SkinT), (b) after renal transplantation, and (c) after adoptive transfer of sensitized serum. DSA IgG and IgM levels were determined by flow cytometry and converted to MESF units. The control was a no-treatment rat. In the presensitized (PS) group, renal transplantation was performed 14 days after skin transplantation. Data are given as means±s.d. AT, adoptive transfer group; NS, nonsensitized group. †NS, not significant. *P<0.05 and **P<0.01 versus the control group. Kidney International 2013 84, 722-732DOI: (10.1038/ki.2013.117) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 2 Renal function and survival. (a) The mean serum creatinine (sCr) of the presensitized (PS group) increased steadily after renal transplantation, whereas sCr decreased in the other groups after 24h (syngeneic (SY): n=6, nonsensitized (NS): n=7, and PS: n=8). (b) Survival in the NS group was 8.7±1.6 days, whereas that in the PS group was 4.4±1.3 days. P=0.015, NS versus PS groups, log-rank test (SY: n=7, NS: n=6, and PS: n=7). Kidney International 2013 84, 722-732DOI: (10.1038/ki.2013.117) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 3 Histopathology and C4d staining. In the nonsensitized (NS) group, there was no histological finding in any kidney sample section from 2 to 12h (A-1–3). Minimal inflammation in peritubular capillaries (PTCs) was first seen in the 72h allograft and progressed over time (A-6). In contrast, in the presensitized (PS) group, PTCs were dilated beginning from 2h after transplantation, and there were neutrophil and mononuclear cell infiltrates in these capillaries (B-1). Later, peritubular capillaritis worsened. All samples from the sensitized model at 72 and 96h after transplantation revealed severe peritubular capillaritis (B-6, 7). In the NS group, transplant glomerulitis was not seen within 72h; mild inflammation in glomeruli was seen at 96h (A-7), and moderate-to-severe glomerulitis was observed at 120 and 168h (A-8, 9). In the PS group, glomerular capillaries had mild cellular infiltration with mononuclear cells, neutrophils, and reactive endothelial cells at 48h (B-5). Obvious inflammation was found after 72h, and some glomeruli revealed thrombotic microangiopathy at 96h after transplantation (B-6, 7; arrows). In the adoptive transfer (AT) model, PTCs were dilated 2 and 6h after transplantation, but there was no infiltration of neutrophils or mononuclear cells in these capillaries (C-1, 2; arrowheads). The AT group showed similar changes to those in the NS group. Tubulitis was detectable only during the end stages of rejection in all three groups. In the PS group, C4d staining on PTCs was weakly positive (<10%, C4d1) beginning 2h after transplantation (E-1). Focal C4d (10–50%, C4d2) positive staining of kidney tissue was seen at 6 and 12h (E-2, 3). All samples after 24h revealed diffuse, bright staining of PTCs for C4d (>50%, C4d3) in the PS model (E-4–7). On the other hand, C4d-positive PTC was absent from 2 to 72h (D-1–6) and minimal at 96h in the NS group (D-7). Specimens obtained at 120 and 168h in nonsensitized recipients demonstrated bright, linear staining of PTC for C4d (D-8, 9). In the AT model, C4d staining of PTC was weakly positive at 6 and 12h after transplantation (F-2, 3), but became negative from 12 to 96h postoperatively (F-4–7) before again becoming positive from 120h after transplantation (F-8). PAS, periodic acid–Schiff. Kidney International 2013 84, 722-732DOI: (10.1038/ki.2013.117) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 4 Immunoglobulin G (IgG) staining. In the grafts of the presensitized (PS) model, anti-IgG stained glomerular capillaries and peritubular capillaries from 2h after transplantation (H-1), but no staining for IgG was observed in the nonsensitized (NS) model at this time (G-1). In the grafts of the NS model, the anti-IgG antibody stained glomerular capillaries and peritubular capillaries from 120h after transplantation. In the adoptive transfer (AT) model, anti-IgG was weakly positive from 6h after transplantation; this staining level persisted for 168h postoperatively. IgG staining scores are: negative=0, minimal to mild=1, and more than moderate=2. Kidney International 2013 84, 722-732DOI: (10.1038/ki.2013.117) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 5 Sequential analysis of C1q, C3, tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and interleukin-1β (IL-1β) after renal transplantation. Levels of (a) C1q, (b) C3, (c) TNF-α, (d) MCP-1, (e) ICAM-1, and (f) IL-1β in the renal graft were measured in homogenized tissue supernatants using commercially available solid-phase enzyme-linked immunosorbent assays (ELISAs). The control was a no-treatment rat. Data are means±s.d. †NS, not significant, *P<0.05 and **P<0.01 versus the control group. AT, adoptive transfer group; NS, nonsensitized group; PS, presensitized group; SY, syngeneic group. Kidney International 2013 84, 722-732DOI: (10.1038/ki.2013.117) Copyright © 2013 International Society of Nephrology Terms and Conditions