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Nine Years Experience with Desensitization of Living Donor

Transplant Recipients

Royal Society of MedicineLondon, England

June 1, 2007

Stephen T. Bartlett, M.D.Barbara Baur Dunlap Professor

Chairman, Department of SurgeryUniversity of Maryland School of Medicine

Surgeon-in-Chief,University of Maryland Medical Center

Sources of HLA Sensitization

• Blood transfusionBlood transfusion• Prior transplantationPrior transplantation• PregnancyPregnancy• Others? Others? Among patients receiving their first Among patients receiving their first

kidney transplant with no known history of blood kidney transplant with no known history of blood transfusions, approximately 20% of nulliparous transfusions, approximately 20% of nulliparous women and 13% of men were sensitized women and 13% of men were sensitized (PRA>10%). ?unreported or unrecognized (PRA>10%). ?unreported or unrecognized pregnancies or transfusions, ?antigenic stimulation pregnancies or transfusions, ?antigenic stimulation of sperm. ?cross-reacting environmental allergensof sperm. ?cross-reacting environmental allergens

Sources of Sensitization: IISources of Sensitization: II

Hardy, Lee and Terasaki; Clinical Transplants 2001

Prevalence of Sensitization

• UNOS: 30% of patients on the transplant wait UNOS: 30% of patients on the transplant wait list have a PRA of > 20%list have a PRA of > 20%– New England Organ Bank: 56% with New England Organ Bank: 56% with

PRA>50%, 28% with PRA 90-100%.PRA>50%, 28% with PRA 90-100%.• Accumulation phenomenon: the mean waiting Accumulation phenomenon: the mean waiting

time for prospective recipients with PRA > time for prospective recipients with PRA > 50% is 26.2 months, five times longer than 50% is 26.2 months, five times longer than that for unsensitized recipients with a PRA that for unsensitized recipients with a PRA below 10 percent.below 10 percent.

The Status of Transplantation 1998:Why consider desensitization?

• ABO Experience Japan – fair outcomesABO Experience Japan – fair outcomes

U.S. Standard was avoidance PPCN cross U.S. Standard was avoidance PPCN cross match unless the patient has negative match unless the patient has negative cross match on archived serum cross match on archived serum ≥≥ 6 6 monthsmonths

Why Believe Desensitization Should Succeed?

• Two cases in same week for cadaver transplantTwo cases in same week for cadaver transplant

-- Two recipients with known marked sensitization Two recipients with known marked sensitization presented for transplants; two samples for cross presented for transplants; two samples for cross matching drawn approximately one week apart; matching drawn approximately one week apart; first positive AHG cross match, second negativefirst positive AHG cross match, second negative

-- Transplants done successfully with 10 day T Transplants done successfully with 10 day T cell depletion with OKT3cell depletion with OKT3

Hypothesis at time: with newer anti-T cell depleting Hypothesis at time: with newer anti-T cell depleting agents, perhaps Ab depletion will work since only agents, perhaps Ab depletion will work since only need to be cross match negative currently, even for just need to be cross match negative currently, even for just one dayone day

Pros and Cons of PP/IVIG

• AdvantagesAdvantages– High efficacyHigh efficacy– Somewhat predictable Somewhat predictable

responseresponse– Monitoring DSA Monitoring DSA

possiblepossible– Double-incompatibility Double-incompatibility

possiblepossible

• DisadvantagesDisadvantages– ExpensiveExpensive– Labor intensiveLabor intensive– Only for LDOnly for LD– Rebound possibleRebound possible– Adverse effectsAdverse effects

Schweitzer Protocol

• Began protocol 1998 of PP/IVIG to Began protocol 1998 of PP/IVIG to convert current positive T cell AHG to convert current positive T cell AHG to negativenegative

University of MarylandProtocol Overview

Tx

0 1 2 3-1-2-3-4-5-6-7-8-9-10

PP/Ig

Anti-CD20

FK 506MPA

SteroidsThymoglobulin

PP/Ig PP/Ig PP/Ig PP/Ig

Time in days

DSA Testing

4

UMM Protocol

ImmunosuppressionImmunosuppression

MMF 2 g/d, started 3 days prior to 1MMF 2 g/d, started 3 days prior to 1stst PP PP

FK506 started on 1FK506 started on 1stst day of PP, target level 15 day of PP, target level 15 ng/mlng/ml

Prednisone 0.25 mg/kg BID with FK506Prednisone 0.25 mg/kg BID with FK506

Induction with OKT3, 5 mg/d x 10 days with Induction with OKT3, 5 mg/d x 10 days with target CD3 <5%target CD3 <5%

Transplantation 2000; 70:1531

UMM Protocol

• 15 patients, including 2 with SPLK15 patients, including 2 with SPLK• Positive AHG-CDC XMPositive AHG-CDC XM• All DSA anti-HLA class I Ab’s by ELISAAll DSA anti-HLA class I Ab’s by ELISA• Mean peak PRA 69% (44-95%)Mean peak PRA 69% (44-95%)• AHG titer at evaluation 2-16AHG titer at evaluation 2-16• AHG titer at start 1-16, many with lower titers AHG titer at start 1-16, many with lower titers

compared to time of evaluationcompared to time of evaluation• 4 did not convert to negative XM with therapy, 4 did not convert to negative XM with therapy,

so were not transplantedso were not transplanted

Transplantation 2000; 70:1531

0

20

40

60

80

100

0 6 12 18 24 30 36 42 48

Months

Gra

ft S

urvi

val (

%)

Protocol (n = 16)Contemporaneous (n = 530)

Patients (1998-2007)

Total – 52Total – 52

Average Age Average Age 41.7yr (17–67) 41.7yr (17–67)

Male/Female Male/Female 68.3%/32.7%68.3%/32.7%

RaceRace White (36)White (36) 69.2%69.2%AA (14)AA (14) 26.9%26.9%Asian (1)Asian (1) 1.9%1.9%Hisp (1)Hisp (1) 1.9%1.9%

DONOR DEMOGRAPHICS

204+49 secs208+107 secsWarm ischemia

27.7+6.428.6+5.1BMI Female

27.6+4.227.1+4.1BMI Male

0.8+0.1 mg%0.8+0.1 mg%SCR Female

1.0+0.1 mg%1.0+0.1 mg%SCR Male

40.4+11.4 yrs40.1+10.8 yrsAge

27%27%AA

42%56%Male

1000 LRD TXSTUDY GROUP

Immunologic Risk

Pts. w/ previous TxPts. w/ previous Tx 15 15 HLA MM (Ave.) -HLA MM (Ave.) - 3.83.8Peak PRA > 30Peak PRA > 30 80.7% (Class 1) 80.7% (Class 1) PRA @ Tx > 30 PRA @ Tx > 30 30.7%30.7%Relation to DonorRelation to Donor11stst/2/2ndnd/Unrelated/Unrelated 31/4/1731/4/17Ave # PP Pre-TxAve # PP Pre-Tx 3.4 (1-12)3.4 (1-12)Ave # PP PostAve # PP Post 8 (1-18)8 (1-18)

** Only in 7 pts. for early AMR** Only in 7 pts. for early AMR

Immunologic Profile - 52pts

T–Cell AHG +T–Cell AHG + 1919– Titers of 1:4 or lessTiters of 1:4 or less– 1 remained Pos following Rx1 remained Pos following Rx

B–Cell CDC +B–Cell CDC + 1616– Titers of 1:8 or lessTiters of 1:8 or less– 5 remained Pos following Rx5 remained Pos following Rx

Immunologic Profile - 52pts

T-Cell Flow + (AHG -) 23– 15 remained Pos following Rx15 remained Pos following Rx– 5/8 AHG+ -> AHG- remained5/8 AHG+ -> AHG- remained

flow + following Rxflow + following Rx

B-Cell Flow + (CDC -) 27– 12 remained Pos following Rx12 remained Pos following Rx– 3/5 CDC+ -> CDC- remained3/5 CDC+ -> CDC- remained

flow + following Rxflow + following Rx

T and B-Cell Flow + 15– 11 remained Pos following Rx11 remained Pos following Rx

Patient Survival in LD Transplants

0.00

0.25

0.50

0.75

1.00

0 2 4 6 8 10Analysis time (year)

Control groupN=951

+XM groupN=52

Kaplan-Meier patient survival estimates

P=0.22

Unadjusted HR: 1.5, P=0.22 (95% CI:0.77-3.0)

Control group1-yr survival: 96.5%

5-yr survival:85%

Study group1-yr survival: 94%5-yr survival:74%

Graft Survival in LD Transplants

0.00

0.25

0.50

0.75

1.000 2 4 6 8 10

Analysis time (year)

Control groupN=951

+ XM groupN=52

Kaplan-Meier graft survival estimates

P=0.006

Control group1-yr survival: 94%5-yr survival:74%

Study group1-yr survival: 86%5-yr survival:62%

Unadjusted HR: 1.9, P=0.007 (95% CI:1.2-3.1)

Graft Survival vs. Patients Matched for re-Tx Status, Race, Sex, and Age

P=0.024

Unadjusted HR=2.5, P=0.029; 95%CI(1.1-5.7)

0.00

0.25

0.50

0.75

1.000 2 4 6 8 10

Analysis time (year)

Matched control groupN=52

+ XM groupN=52

Kaplan-Meier graft survival estimates

Control group1-yr survival: 100%5-yr survival:82%

Study group1-yr survival: 86%5-yr survival:62%

P=0.024

Patient Survival, Matched Groups

0.00

0.25

0.50

0.75

1.000 2 4 6 8 10

Analysis time (year)

Matched control groupN=52

+ XM groupN=52

Kaplan-Meier patient survival estimates

Unadjusted HR=4.3, P=0.061; (95%CI:0.93-20.0)

P=0.04

Control group1-yr survival: 100%5-yr survival:90.3%

Study group1-yr survival: 98%

5-yr survival:77.2%

Serum Creatinine

0.00

0.50

1.00

1.50

2.00

2.50

1 2 3 4 5

YEARS

Creatinine

study group controls

p=NS

Proteinuria-free* at Most Recent Followup

0%

10%

20%

30%

40%

50%

60%

70%

1st Qtr

3-D Column 1

68.4%

*<300 mg/dl or <1+. Only one patient had > 1 gram per day proteinuria

Criteria for AMR

Detection of DSA in recipient serumDetection of DSA in recipient serumAllograft dysfunctionAllograft dysfunctionCharacteristic histological features including:Characteristic histological features including:

1) glomerulitis/capillaritis1) glomerulitis/capillaritis2) margination of neutrophils in the PTC2) margination of neutrophils in the PTC3) severe or necrotizing vasculitis3) severe or necrotizing vasculitis4) interstitial hemorrhage4) interstitial hemorrhage5) fibrin thrombi5) fibrin thrombi

**Diffuse, linear C4d staining in the PTC**Diffuse, linear C4d staining in the PTC

Acute Rejection During First Year

Survival Function

stb time to ar or censor

4003002001000-100

Cu

m S

urv

iva

l

1.1

1.0

.9

.8

.7

.6

Survival Function

Censored

Days post-transplant

•28.8% Pts with rejection episodes in first post-transpant year•13.5% Pts with rejection episodes in first 10 days post-transplant

Acute Rejection During First Year Compared to Other Recipients of Live

Donor GraftsSurvival Functions

stb time to ar or censor

4003002001000-100

Cu

m S

urv

iva

l

1.1

1.0

.9

.8

.7

.6

desen STB study

1

1-censored

0

0-censored

Days post-transplant

Log rank p=0.03

Biopsy Findings in “For Cause” Biopsies22/52 (42%)

22%

14.30%

10.40%

4.20%

10.20%

6%

0%

5%

10%

15%

20%

25%

1

AMR

ACR

TG

CVR

TMA

PVN

Graft Survival by Retransplantation

0.00

0.25

0.50

0.75

1.000 2 4 6 8 10

Analysis time (year)

1st graftN=39

Re-graftN=13

Kaplan-Meier graft survival estimates

Unadjusted HR=2.4, P=0.067; (95%CI:0.94-6.1)

P=0.058

Graft Survival, by Peak PRA (Class I)

0.00

0.25

0.50

0.75

1.00

0 2 4 6 8 10Analysis time (year)

PRA<20 20≤PRA<80

PRA≥80

Kaplan-Meier graft survival estimates

Unadjusted HR for P-PRA 20-80: 2.8, P=0.38; for P-PRA>80: 5.8, P=0.10

P=0.12

Graft Survival, by XM Methodology

0.00

0.25

0.50

0.75

1.000 2 4 6 8 10

Analysis time (year)

FCXM AHG/CDC

Kaplan-Meier graft survival estimates

Unadjusted HR=0.92, P=0.87; (95%CI:0.34-2.4)

Graft Survival if Both Pre-op T-cell and B-cell Reactions Negative

0.00

0.25

0.50

0.75

1.000 2 4 6 8 10

Analysis time (year)

Positive XM Negative XM

Kaplan-Meier graft survival estimates

Unadjusted HR=0.37, P=0.053; (95%CI:0.14-1.01)

P=0.044

Graft Survival, by Pre-op T-cell Reaction

0.00

0.25

0.50

0.75

1.00

0 2 4 6 8 10Analysis time (year)

Positive Negative

Kaplan-Meier graft survival estimates

Unadjusted HR=0.27, P=0.01; (95%CI:0.01-0.73)

P=0.006

Mayo Clinic Experience-2006

AJT 2006, 6:346

p < 0.05 IVIG vs. PP groups

Summary Outcomes at 3 Centers

1.5±0.4 (at 5 yr)3687% (at 5 yr)97% (at 5 yr)HD IVIGCSMC/96

1.2±0.3 (at 3 yr)6280.9% (at 3 yr)95% (at 3 yr)PP/CMVIGJHU/90

1.6±0.6 (at 5 yr)35 80% (at 5 yr)95% (at 5 yr)

HD IVIG

PP/LD

IVIG

Mayo clinic/90

Mean S Cr (mg/dl)

AR (%)Graft survivalPt survivalProtocolTransplant program/Pt

Prospective Analysis Presence of Anti-HLA Antibodies After Transplantation

• Frequency HLA – Ab after transplant in 4,763 ptsFrequency HLA – Ab after transplant in 4,763 ptsKidney 20.9% CsA– Aza 18.1 %Kidney 20.9% CsA– Aza 18.1 %

CsA- MMF 9.8%CsA- MMF 9.8%

Liver 19.3 %Liver 19.3 %

- Heart 22.8 %Heart 22.8 %

• 1 Year later 91 grafts failed

• 6.6 % graft failures with detectable HLA – Ab

3.3% without graft failure have HLA-Ab

• De Novo Ab 8.0% graft failures HLA – Ab detectable

3.0% without graft failure have detectable Ab Terasoki: AJT 2004 (4), 4.39

Clinical Implications of DSA and non-DSA (NDSA) after Renal

Transplantation

Hourmant, JSAN 2005(1b), 2804.

•Five year prospective study of 1,229 kidney recipients

FREQUENCYGRAFT LOSS

DSA: 5.5% 15%

NDSA: 11.3% 18%

NONE: 83% 6.5%

•Risk factors: HLA-DR match, pre-transplant sensitization, rejection

•DSA and NDSA associated with lower graft survival, poor function and proteinuria

Graft Accommodation

• Acceptance of graft despite presence of DSA. Acceptance of graft despite presence of DSA. • MechanismsMechanisms

- - upregulation of complement regulatory upregulation of complement regulatory mechanisms: thus C4d stain may be salutary in mechanisms: thus C4d stain may be salutary in absence of signs of injury absence of signs of injury - replacement of graft donor endothelial cells - replacement of graft donor endothelial cells with recipient endothelium with recipient endothelium - appearance of anti-apoptotic protein BCL-2, - appearance of anti-apoptotic protein BCL-2, BCL-X, HO – 1BCL-X, HO – 1

Conclusions

Desensitization protocols in living donor transplantationDesensitization protocols in living donor transplantation

-- Accelerate transplantation relative to deceased Accelerate transplantation relative to deceased donor wait listingdonor wait listing

-- Results approximately equal to ECD DD Results approximately equal to ECD DD transplants at 5 yearstransplants at 5 years

-- Unpredictable rejection most common Unpredictable rejection most common complicationcomplication

-- Infectious complications remarkably rareInfectious complications remarkably rare

-- Plasmapheresis carries risk in patients with Plasmapheresis carries risk in patients with cardiovascular diseasecardiovascular disease

Conclusions

High Risk ScenariosHigh Risk Scenarios

Donor specific antibody (DSA) as Donor specific antibody (DSA) as consequence of renal rejection – (versus consequence of renal rejection – (versus transfusion) particularly early AMRtransfusion) particularly early AMR

Repeat HLA-Ag mismatch in setting of Repeat HLA-Ag mismatch in setting of DSA to repeat mismatchDSA to repeat mismatch

Prior early AMRPrior early AMR

Future Studies

• Clearer epidemiologic data on non-pathologic Clearer epidemiologic data on non-pathologic – “beneficial” re-appearance of DSA– “beneficial” re-appearance of DSA

-- Is all DSA harmful but with varying pace Is all DSA harmful but with varying pace of pathologic injury?of pathologic injury?

-- Is accommodation present in humans?Is accommodation present in humans?Prospective, multi-center trial with protocol Prospective, multi-center trial with protocol biopsy to 5-8 years could answer question biopsy to 5-8 years could answer question regarding pathogenic versus beneficial effect of regarding pathogenic versus beneficial effect of DSA re-appearanceDSA re-appearance