Case report: 36y African origin - bvn-sbn.be C4d... · Mildly positive to multiple antigen...

11/01/2017

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DSA, C4d, Antibody-mediated rejection:

Diagnostic and therapeutic challenges

Jean-Louis Bosmans,

University Hospital Antwerpen

Liesbeth Daniëls,

HILA Red Cross Flanders

1 BVN/SBN 15 December 2016

Case report: ♂ 36y African origin

• Chronic GN (unspecified)

• 09/2010 1st kidney graft

• 4/6 HLA MM: 1A, 1B, 1DR, 1DQ

• Induction IS: ATG/MP

• Maintenance IS: Predni, MMF, CsA


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• 12/2014: acute, oliguric ARF after prolonged travel in Africa

• Tx kidney biopsy

• Treatment with MP, plasmapheresis and IgG

• No recovery

• Transplantectomy 12/2014



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• 12/2014: acute, oliguric ARF after prolonged travel in Africa

• Tx kidney biopsy

• Treatment with MP, plasmapheresis and IgG

• No recovery

• Transplantectomy 12/2014



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DSA

Understanding the complexities and limitations of DSA detection

techniques is key for making an accurate risk assessment while

improving access to transplantation.

Risk estimation

HLA antibodies

Waiting time on transplant list

(morbidity, death)


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CDC / FCM

Complement Dependent Cytotoxicity • CDC Ab Screening Cytotoxic – IgG/M (DTT) – HLA Ab

• CDC XM T (Class I)/B (Class I +II) lymphocytes

• Unacceptable Antigens

• Virtual XM

Flow Cytometry • Luminex Ab screening (beads) (Non-)Cytotoxic – IgG – HLA Ab

• FCXM T(Class I)/B(Class I+II)lymphocytes


CDC / Luminex

Positive CDC (Allo-IgG):

- Contra-indication for TX

- Low sensitivity and specificity

Luminex only, positive:

- Risk factor for TX

- High sensitivity


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Case report: HLA match

Patient HLA typing

A2 A32 (A19)

B71 (B70) B57 (B17)

Cw18 Cw10 (Cw3)

DR7 DR11 (DR5)

DQ2 DQ7(DQ3)

Donor ET 134333 HLA typing

A2 A29 (A19)

B50 (B21) B58 (B17)

DR7 DR8

DQ2 DQ4

Eurotransplant HLA match: 4/6


Luminex data

DSA: anti-A29, anti-B50 DSA: anti-DR8, anti-DQ4 14 BVN/SBN 15 December 2016

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Case report: HLA match

Patient HLA typing

A2 A32 (A19)

B71 (B70) B57 (B17)

Cw18 Cw10 (Cw3)

DR7 DR11 (DR5)

DQ2 DQ7(DQ3)

Donor ET 134333 HLA typing

A2 A29 (A19)

B50 (B21) B58 (B17)

DR7 DR8

DQ2 DQ4

HLA match: 2/6


Luminex / FCXM / CDC XM

AMR Risk Considerations Luminex SA FCXM CDC XM

Low

No DSA present Neg Neg Neg

Alloantibody towards denatured HLA Pos Neg Neg

Laboratory factors Pos Neg Neg

Recent anti-CD20 treatment Neg Pos Pos

Auto-antibodies Neg Pos Pos

High

DSA present Pos Pos

Pos due to Cytotoxic IgG DSA

=> VETO

Alloantibody to shared epitope Weakly Pos Pos

Prozone effect Weakly Pos strongly Pos

Incomplete donor/recipient HLA typing Neg Pos

Uncertain

Low HLA expression on donor cells (Cw) Pos Neg Neg

DSA with low affinity/avidity Pos Neg Neg

Non-HLA antibody Weakly pos or Neg Pos Pos

Interpreting anti-HLA antibody testing data: a practical guide for physicians. Schinstock et al. Transplantation 2016.


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MFI values do not always translate into antibody level

Laboratory factors: - Inter-laboratory variability

• Differences in the SAB product itself depending on the bead manufacturer, batch or lot. • Manufacturers have different antigen sources, distinctive specificity representation, and varied

antigen density on the beads.

- Intra-laboratory variability • Laboratory personnel, reagents, equipment, and conditions.

- Background fluorescence Mildly positive to multiple antigen specificities (without a sensitizing event) The variation in MFI has been reported as high as 62%, especially when the MFI is relatively low

(1000-3000).

Prozone: Weakly positive but in fact strongly reactive HLA Ab


Prozone - C1 binds to two or more closely adjacent IgG molecules - C1 consists of C1q and Ca2+ dependent C1r-C1s tetramer - C1r-C1s tetramer blocks probably that part of the Fc region, which the anti-IgG detection antibody

binds to. - EDTA chelates Ca2+ ions, dissociating the C1r-C1s subunit from C1q, abolishing the prozone effect. - When serum contains HLA antibodies with a lower titer, not all of the HLA antigens on the beads are

covered by IgG, leaving spaces between the IgG molecules, which prevent C1 from binding, but allow the anti-IgG detection antibodies to catch their targets.

IgG antibody

C1q

HLA antigen

Ca2+ dependent tetramer C1r-C1s

HLA antibody specification using single-antigen beads – A technical solution for the prozone effect. Schnaidt et al. Transplant journal 2011.


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Wiebe C et al. Am J Transplant 2016; XX: 1-9


Luminex / FCXM / CDC XM

AMR Risk Considerations Luminex SA FCXM CDC XM

Low

No DSA present Neg Neg Neg

Alloantibody towards denatured HLA Pos Neg Neg

Laboratory factors Pos Neg Neg

Recent anti-CD20 treatment Neg Pos Pos

Auto-antibodies Neg Pos Pos

High

DSA present Pos Pos

Pos due to Cytotoxic IgG DSA

=> VETO

Alloantibody to shared epitope Weakly Pos Pos

Prozone effect Weakly Pos strongly Pos

Incomplete donor/recipient HLA typing Neg Pos

Uncertain

Low HLA expression on donor cells (Cw) Pos Neg Neg

DSA with low affinity/avidity Pos Neg Neg

Non-HLA antibody Weakly pos or Neg Pos Pos

Interpreting anti-HLA antibody testing data: a practical guide for physicians. Schinstock et al. Transplantation 2016.


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New techniques to evaluate DSA pathogenicity

- Flow cytometry measurement of IgG subclasses

- Luminex measurement of complement binding antibodies (C1q,C3d)

- Surface plasmon resonance (Antibody affinity)

- ELISPOT measurement of memory B cells

- Epitope analysis

- …

=> Characterization of the patient’s DSAs and immune repertoire provides a foundation for individualized medicine as well as possible guidelines for the risk stratification of transplantation patients.

The perfect storm: HLA antibodies, complement, FcgRs, and endothelium in transplant rejection. Thomas et al. Trends in Molecular Medicine 2015.


B. Sis, Ph.F.Halloran. Curr Opin Organ Transplant 2010; 15: 42-48 22 BVN/SBN 15 December 2016

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S.C. Jordan & A.A.Vo. Curr Opin Organ Transplant 2014; 19: 591-597 23 BVN/SBN 15 December 2016

BVN/SBN 15 December 2016 24

L-E. Croze et al. Transplant Int 2014;27: 775-783

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Incidence of dnDSA postTx

M.J.Everly & Al. Transplantation 2013;95: 410-417 25

BVN/SBN 15 December 2016

M.J.Everly & Al. Transplantation 2013;95: 410-417 26


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Z. Kicic et al. Clin J Am Soc Nephrol 2015; 10: 1435-1443

C4d +/- ABMR and graft survival

C4d + ABMR and graft function

Z. Kicic et al. Clin J Am Soc Nephrol 2015; 10: 1435-1443 28


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Outcome of DSA’s binding C1q vs DSA with subclass IgG3

D. Viglietti & Al. Am J Soc Nephrol 2016; 28 29


Targetting the DSA’s: plasmapheresis + IVIg

J.E.Cooper & Al. Transplantation 2014; 97:1253-1259


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Transplantation 2010; 89:277-284


Targetting the plasmacells: Bortezomib


F. Eskandary et al. Transplant Int 2016; 29: 392-402

Targetting the complement activation: Eculizumab

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WhatWhat the the nephrologistnephrologist shouldshould knowknow

•• DSA have the DSA have the potentialpotential to to induceinduce microvascularmicrovascular injuryinjury to the to the renalrenal allograftallograft..

•• ThisThis microvascularmicrovascular injuryinjury frequentlyfrequently inducesinduces complement complement activationactivation, , resultingresulting in in C4d C4d depositiondeposition

•• The The microvascularmicrovascular injuryinjury inducedinduced byby DSA (AMR) is DSA (AMR) is oftenoften detrimentaldetrimental to to graftgraft functionfunction and and graftgraft survivalsurvival

•• The The concentrationconcentration of DSA is of DSA is associatedassociated withwith C1Q binding and IgG3. C1Q binding and IgG3. HigherHigher levelslevels of DSA are of DSA are associatedassociated withwith a a worseworse graftgraft prognosis.prognosis.

•• TreatmentTreatment strategiesstrategies withwith plasmapheresisplasmapheresis + IV + IV IgIg, , bortezomibbortezomib, and , and eculizumabeculizumab have have shownshown somesome therapeutictherapeutic effect in effect in termsterms of of reducingreducing DSA DSA titerstiters and and improvingimproving ABMRABMR

•• OurOur knowledgeknowledge in the field of DSA and ABMR is in the field of DSA and ABMR is farfar fromfrom complete and complete and willwill most most likelylikely expandexpand in coming in coming yearsyears withwith the the implementationimplementation of of newnew technologiestechnologies



Case report: 36y African origin - bvn-sbn.be C4d... · Mildly positive to multiple antigen...

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Transcript of Case report: 36y African origin - bvn-sbn.be C4d... · Mildly positive to multiple antigen...