Antibody-Mediated Rejection Experience with Antibody-Mediated Rejection Millie Samaniego, M.D. Associate Professor of Medicine University of Wisconsin and Robert A. Montgomery, M.D., D.Phil. Chief, Division of Transplantation Director, The Johns Hopkins Comprehensive Transplant Center The Johns Hopkins Hospital

Diagnostic Criteria for Acute AMR Characteristic histologic features including: 1) glomerulitis/capillaritis 2) margination of neutrophils in the PTC 3) fibrin thrombi 4) interstitial hemorrhage 5) severe or necrotizing vasculitis Diffuse, linear C4d staining in the PTC Identification of DSA Grade 1 Grade 3

Patterns of Rejection in ABO Incompatible Transplants AMR Cellular Accommodation

Therapeutic Options For The Treatment Of AMR Antibody Reduction Immunomodulation Plasmapheresis/IA IVIg IVIg ATG IL-2R blockers Fk 506, Rapamycin MMF/DSG CAMPATH? B-cell Modulation Splenectomy Anti-CD20 Cytoxan

Antibody Reduction Therapy High dose IVIG (1-2 gms/kg) Mechanism: Anti-idiotypic networks probably important Many putative immunomodulatory pathways identified Advantages: In vitro test for predicting efficacy Ease of administration? Disadvantages: Non-responders Different techniques required to follow DSA titers Less rapid Ab removal, unproven for high-titer DSA Toxicity & batch-to-batch variability Unproven for ABOi Tx

Antibody Reduction Therapy Plasmapheresis/Low Dose IVIg (100 mg/kg) Mechanism: Rapid reduction in anti-HLA or isoagglutinin Ab Induces donor specific unresponsiveness (HLA) or accommodation (ABOI) Advantages: Predictable kinetics of plasmapheresis No evidence of “nonresponders” Able to easily follow DSA levels during/after therapy Disadvantages: DSA may rebound between treatments or if discontinued Treatment may be prolonged and immunosuppressive Expensive and resource intensive

B-Cell Modulation Anti-CD20 Mechanism: Rapid ablation of the peripheral B-cell compartment Advantages: Probably reduces precursor cells responsible for clonal expansion during AMR May produce more effective antibody reduction when combined with plasmapheresis or IVIG Well-tolerated, little apparent toxicity Effect on the immune system is temporary (6-months) Disadvantages: Plasma cells persist in the spleen May not, on its own, reduce DSA titers during AMR Immunosuppressive

Case Study: AMR in (+) Cytotoxic XM with High Titer Anti-HLA DSA DSA titer 512 Cr 6.5 PP/ CMVIg PRA 128 100 Cr 4.4 100 100 100 120 98 90 Cr 2.1 Cr 1.5 Cr 1.6 85 80 100 70 DSA titer 80 60 PRA 64 58 50 60 Anti-CD20 CD20=0 CD19=0 CD20=23.7 40 40 32 32 30 Tx 20 20 16 16 16 16 16 8 8 8 8 8 8 10 4 4 4 2 4 4 2 2 1 1 1 -19 -17 -15 -12 -8 -7 -6 -5 -4 -3 -2 -1 +2 +3 +4 +5 +6 +7 +8 +9 +11 +12 +13 +16 +18 +19 Days from Transplant

B-cell Modulation Splenectomy Mechanism: Reduces plasma cells, precursor cells, B-cell immune surveillance capabilities Advantages: Can be performed using minimally invasive techniques May produce more effective antibody reduction when combined with plasmapheresis or IVIG Disadvantages: Life-long risk of sepsis from encapsulated bacteria Does not appear on its own to reduce DSA titers Effect on immune system is permanent

The Effect of Splenectomy on Anti-Blood Group Ab PP/IVIg 512 256 Splenectomy 4 3 Anti-A Titers (1:X) Serum Creatinine (mg/dL) 128 Tx 2 64 1 32 16 -28 -23 -21 -18 -16-15 -14 -12 -10 -6 -4 -3 -2 -1 3 5 7 8 10 12 14 17 21 25 27 31 32 34 40 42 45 Day With Respect to Transplant

Targets of Strategies for Antibody Removal Plasmapheresis/IVIG Plasma cells Splenectomy Clonal Expansion B-cells & Pre B-cells Anti-CD20

Acute De Novo AMR Occurs in 4-6% of transplants (80-100% fail) By definition the current XM is negative Risk factors include: + historic XM, history of sensitizing event(s), high risk donor/recipient combination Historically suspected only after there is a poor response to anti-lymphocytic agents Diagnosis should be made by histology and demonstration of the appearance of DSA

PP/CMVIg Treatment Protocol for Acute De Novo AMR Plasmapheresis – single plasma volume exchange Steroid bolus -OR- a-thymocyte globulin IVIG – 100mg/kg following each PP treatment (CMV hyperimmune globulin) PP/Ig PP/Ig PP/Ig PP/Ig PP/Ig Dx of AMR 2 4 6 8 Time Relative to Initiation of Therapy (Days) Heparin D/C FK 506 High Grade:

De Novo AMR: Renal Allograft Function 5 10 15 Serum Creatinine (mg/dL) Nadir Rejection 1 Week 1 Month Current * * p<0.001 1994-2003: 22 recipients of deceased or live donor kidney transplants with AMR by Bx or DSA treated with PP/IVIg Mean f/u: 5 1/2 years Median Nadir Cr (IQR) Cr at AMR 1 week Cr 1 month Cr Current Cr 3.3 (2.2 – 7.1) 6.4 (3.2 – 9.3) 4 (2.3 – 7.9) 1.9 (1.5 – 3.0) 1.5 (1.2 – 2.1)

PP/CMVIg Treatment for De Novo AMR 10 20 30 40 50 60 70 80 90 100 365 730 1095 Time (days) Live donor Deceased donor 100 100 Allograft Survival 90 90 80 80 70 70 p = NS Live Deceased 60 60 p = NS 50 50 1-Year: 87.5% 85.8% 40 40 30 30 20 20 3-Year: 87.5% 77.1% 10 10 Add rate of failure with protocol necessitating Rituximab therapy (don’t include patients who received it for severe AMR) 365 365 730 730 1095 1095 Time (days) Time (days) 5-Year: Overall 81.1% Live donor Deceased donor Live donor Deceased donor Kaplan-Meier Estimate of Graft Survival for recipients who developed de novo AMR and were treated with PP/CMVIg therapy

Bx and DSA Proven De Novo AMR LD DD p n 5 13 Median Days to AMR (Range) 11 (8-253) 9 (7-50) 0.25 Median Months F/U 13.6 (4-76) 11.2 (3-89) 0.77

De Novo Renal Function 15 12 9 Serum Creatinine (mg/dL) 6 3 LD DD Creatinine at Biopsy Creatinine 1 week Creatinine 1 mo Current Cr P=NS for comparison between groups at each timepoint

De Novo AMR Allograft Survival 100.00 90.00 80.00 70.00 60.00 Survival (%) 50.00 40.00 30.00 20.00 10.00 0.00 6 12 18 24 30 36 Time (Months) Live Deceased

Rejection and Clinical Outcomes Following (+) XM and ABOi POSITIVE CROSSMATCH ABO INCOMPATIBLE # OF PATIENTS 86 # OF PATIENTS 28 1 2 3 31 12 5 1 2 3 4 1 Previous Txs Previous Txs AMR CELLULAR REJECTION 27/86 (31%) 26/86 (30%) AMR CELLULAR REJECTION 3/28 (11%) 4/28 (14%) SUBCLINICAL AMR SUBCLINICAL CELLULAR 7/86 (8%)* 16/86 (19%) SUBCLINICAL AMR SUBCLINICAL CELLULAR 0/28 (0%) 7/28 (25%) 1-YEAR GRAFT SURVIVAL 3-YEAR GRAFT SURVIVAL 89.8% 80.9% 1-YEAR GRAFT SURVIVAL 3-YEAR GRAFT SURVIVAL 92.9%** 92.9% *Bx @ 1, 3, 6, 12 mos **1 death WNE 1 Noncompliance

(+) XM vs. De Novo AMR De Novo Desensitized p n 18 31 Median Days to AMR (Range) 10 (7-253) 20 (2-634) 0.16 Median Months F/U 12.4 (3-89) 14.1 (0.6-65) 0.76

(+) XM vs. De Novo AMR Outcomes 3 6 9 12 15 Serum Creatinine (mg/dL) PP/CMVIg Desensitized De Novo Rejection Creatinine at Biopsy Creatinine 1 week Creatinine 1 mo Current Cr P=0.04 P=0.01 P=0.002 P=NS between groups at current timepoint

Allograft Survival After AMR (+) XM vs. De Novo 100.00 90.00 80.00 70.00 p=NS 60.00 Survival (%) 50.00 40.00 30.00 Deaths: incompatible group = 7 (1-year = 81.5%, 3-year = 75.5%) , denovo group = 3 (1-year 94.4%, 3-year 81.9%) 20.00 10.00 0.00 6 12 18 24 30 36 Time (Months) (+) XM DeNovo

Kaplan-Meier Estimate of Graft Survival (+) CDC XM @ Time of Tx vs (-) CDC XM 10 20 30 40 50 60 70 80 90 100 % Allograft Survival 120 150 180 210 240 270 300 330 360 Time (Days) + XM @ Tx - XM @ Tx 1 Year Graft Survival p=NS +XM @ Tx - XM @ Tx N= 14 N= 32 92.3% 87.2%

Anti-CD20 Rescue Protocol Inclusion Characteristics Failure to Respond to Plasmapheresis/CMVIg Therapy Poor or Incomplete Clinical Response Persistence of High-Titer DSA Persistence of Histologic Evidence of AMR Initial Histologic Features That Portend Poor Outcome and/or Graft Loss (Grade 2-3 AMR) Study Group Recipients of Deceased or Live Donor Kidneys De novo AMR AMR After Desensitization

Renal Function Following Anti-CD20 Rescue p=0.0003 p=0.01 10 p=0.07 9 p=0.25 8 7 17 recipients undergoing a-CD20 rescue therapy for AMR 6 5 4 3 2 1 Best AMR 2 weeks 1 Month Current Best Cr AMR Cr 2 week Cr 1 month Cr Current Cr Best AMR 2 weeks 1 month Current 1.8 (1.4 – 2.1) 4.3 (2.5 – 6.5) 3.4 (1.9 – 5.4) 2.1 (1.6 – 3.3) 1.7 (1.1 – 2.6)

Kaplan-Meier Estimate of Graft Survival for Anti-CD20 Rescue 100 75 % Survival 50 25 1 2 3 4 5 6 7 8 9 10 11 12 Months Following Anti-CD20 Treatment

Splenectomy Rescue N 4 Median Days to AMR (Range) (2-15) Median Days to Splenectomy Following AMR Dx 1 (1-4) Median SCr at Biopsy Dx 3.4 (1.5 – 6.0) Median SCr 1 week 2.1 (0.8 – 5.8) Median SCr 1 month 1.5 (0.7 – 2.3) Median Current SCr 1.3 (1.2 – 2.6) Allograft Survival 100% Median Months Followup 6.9 (2.2 – 11.7)

Paired Donation May Reduce the Incidence of AMR Conventional KPD Unconventional KPD A B ABOi A ABOi O B A ABOi O (+) XM A # of KPD: 6 (12 patients) # of KPD: 5 (13 patients) Mean PRA: 14 Mean PRA: 58 6 mos Cr: 1.2 mg/dl 6 mos Cr: 1.1 mg/dl AMR: 0% Cellular 8% AMR: 0% Cellular 23% Patient Survival: 100% Patient Survival: 100% Graft Survival: 91.7% Graft Survival: 100%

Summary The diagnosis of AMR can now be made with a high level of certainty There are therapeutic interventions for AMR with clinically proven efficacy De novo AMR has a good long-term prognosis when treated with PP or IVIg Results of PP or IVIg treatment for De novo AMR and AMR in the setting of desensitization are comparable A (+) cytotoxic XM at the time of Tx does not predict a worse outcome AMR recalcitrant to PP/IVIg is associated with a lower graft survival rate Results of emergent splenectomy at the time of severe AMR look promising KPD may decrease AMR by lowering immunologic risk

Algorithm For Approach To AMR De Novo AMR AMR after (+) XM AMR after ABOi PP/IVIg Severe AMR Response Incomplete Response Anti-CD20 Splenectomy Observe Anti-CD20

Acknowledgements Johns Hopkins InKTP Johns Hopkins InKTP Columbia Matt Cooper Lorraine Racusen Mark Haas Karen King Andrea Zachary Susie Lefell Donna Lucas Julie Graziani Renato Vega Chris Sonnenday Dan Warren Chris Simpkins Janet Hiller Jennie Rickard Amie Swardson James Burdick Edward Kraus Hamid Rabb Richard Ugarte Brigitte Reeb Mary Jo Holechek Diane Lepley Dorry Segev Tomasz Kazlowski Columbia Lloyd Ratner