Pathophysiology, Treatment & Prevention of Antibody - wi

Antibody-Mediated Rejection: Prevention, Pathophysiology,Treatment, Brenda Muth, RN, MS, ACNP Transplant Nephrology and Desensitization

Objectives Define rejection Acute vs Chronic Clinical vs subclinical rejection AMR, ACR, mixed

Discuss prevention of AMR Review immunologic components involved in AMR Review diagnosis of acute AMR Examine treatment options Current therapies Novel treatment including off-label use

UW protocols for AMR treatment

Definitions AMR Graft rejection caused by Ab directed against HLA molecules, ABO antigens or endothelial cell antigens

Clinical Rejection Biopsy confirmed with associated graft dysfunction

Subclinical Rejection Histological changes specific for acute rejection on protocol biopsy w/o graft dysfunction

Definitions • Hyperacute Rejection – Due to preformed Ab

• Early AMR – Due to amnestic Ab response

• Late AMR – Due to de novo DSA production

• Chronic AMR – Recall secondary DSA response

• Mixed rejection • Accomodation – Resistance to injury in presence of Ab

Lymphocytes Myeloid Stem cell

Lymphoid Stem Cell

SC

Lymphoblast

T

PC

B

NK

CD 20

The sequence of letters & numbers identify which HLA gene it is & it’s location HLA-DQB3*0101 (DR52)

Gene

Specific HLA protein Allele (alternate form of the same gene)

Pathophysiology of AMR Donor Organ Capillary Endothelial cell

C1 complex

4

Damaged Cell Releases platelet aggregation factors, cytokines

Formation of Antigen-Ab complex

 C4  C4b  C4d

Endothelial cell necrosis

C4d is by-product and marker of complement activation Schwartz, NEJM 2010

Prognosis of AMR • Vasculopathy • Fibrosis • Loss of graft function/graft loss

Diagnostic Criteria for Kidney AMR Must have at least 2 of the following • Presence of anti-donor antibodies • C4d staining – C4d1: – C4d2: – C4d3:

Minimal C4d stain/detection: 150%

• Morphologic evidence of tissue injury – Capillary and or glomerular inflammation (ptc/g >0) and/or thromboses

• Graft dysfunction

Diagnostic criteria for Pancreas AMR • Acute AMR: (all 3 criteria) – Circulating DSA – morphologic evidence of microvascular tissue injury – C4d staining of interacinar capillaries

• Suspicious for AMR – 2 of 3 criteria

Drachenberg et all, AJT 2011(9)

Consensus Statement for Heart AMR • Based on pathology: – Histology • • • • •

Endothelial activation Intravascular macrophages Neutrophilic infiltrates Capillary destruction Interstitial edema, hemorrhage

– Immunopathology

• May include DSA, graft dysfunction Kobashigawa et al, Journal of Heart and Lung Tx, 2011 (3).

Diagnostic Criteria for Liver AMR • Lack of clear criteria for diagnosis. • May include: – Positive C4d staining of sinusoidal endothelium – Proliferation of small bile ducts – Sinusoidal accumulation of neutrophils – cholestasis

Kozlowski, et al, Liver Transplantation, 2011

Diagnostic Criteria for Lung AMR • Difficult to diagnose • May be determined by prominence of B cells and plasma cells in inflammatory infiltrate, endothelialitis and small airway inflammation

Takemoto et al, AJT, 2004

Antibody mediated rejection

Peritubular capillaritis and focal interstitial hemorrhage

Nickeleit, Neph Dial and Transplant 18: 2232-2239, 2003

Peritubular capillary Immunofluorescent Staining for C4d

Peritubular capillary Immunohistochemistry staining for C4d.

Nickeleit, Neph Dial and Transplant 18: 2232-2239, 2003

CD 20

AMR Treatment T PC

AMR Treatment • • • •

Suppression of T cell response Elimination of circulating Ab Inhibition of Ab Suppression/Depletion of B cells

Suppression of T-cell Response Depletional Antilymphocyte Ab (rATG) • Has multiple anti-T cell Ab specificities, costimulatory pathways, cell adhesion molecules, cell surface molecules expressed on B cells and plasma cells. • Usually used as adjuvant therapy in AMR • Used for severe or steroid resistant ACR • FDA approved for Kidney transplant rejection

Steroids • inhibits IL-1,IL-2, IL-6 production, T-cell proliferation, cytokine gene transcription & antigen presentation

MPA • Prevents proliferation of T & B-cells • FDA approved for kidney

CNI • Both CsA & Tac inhibit T & B-cell activation and proliferation • FDA approved for kidney, liver, heart Singh et al, Transplantation Review, 2009 Samaniego et al, Nature Clinical Practice, 2006 micromedex

Elimination of Circulating Ab Plasmapheresis • Fast, effective method of eliminating DSA • Used in combination with other therapies • Adverse effects: – Nonselective removal of proteins, bleeding diatheses, volume contraction, requires replacement fluid (albumin), allergic reactions, bld borne pathogens, need HD access

• Dose: – 1-1.5 total plasma volume QD or QOD (3 to 6 treatments), followed by maintenance PP – Decision to stop PP should be based on: • elimination of donor-directed HLA antibody • establishment of good graft function • graft failure

• Cost: ~ $2000.00 per treatment Apheresis Guidelines considered a therapeutic option when AMR has been confirmed by Bx and/or + DSA & immunosuppressive treatment has not been effective. Singh et al, Transplantation Review, 2009 Apheresis Guidelines, 2009

Inhibition of Antibody Immune Globulin Highly purified IgG from large pools of human plasma diluted in sterile water +/- glucose, sodium. Non-FDA labeled use • Action: – immunomodulatory effects on T cells, macrophages, cytokine synthesis, B-cell function & regulatory action on complement system – Down regulates antibody/blocks HLA Ab from binding to targets – T & B cell suppression

• Adverse effects: – Arthralgias, mylagias, HA, HTN, hypotension, MI, Hypercoagulability, allergic reactions, volume overload, AKI

• Dose: – T ½ = 3 weeks – Range 100 mg/kg to 2 gm/kg – ~ $500.00 for 100mg/kg dose Singh et al, Transplantation Review, 2009 Micromedex

Suppression/Depletion of B-cells Rituximab Genetically engineered chimeric MoAb w/ mouse fused with human IgG. • Indication: – FDA approved for Non-hodgkin’s Lymphoma, rheumatoid arthritis. Use for AMR is off label.

• Action:

– binds to the CD20 antigen located on pre-B & mature B lymphocytes: mediates B cell lysis – Depletes CD19 & CD20 (Chemical splenectomy) – No effect on plasma cells

• Adverse effects:

– Infusion and hypersensitivity reactions, cytopenias, fever,  infection risk including association with BK

• Dose

– 375 mg/m2 BSA IV – Duration of treatment ? – ~ $650.00

Singh et al, Transplantation Review, 2009 Micromedex

Depletion of Plasma cell Bortezomib Reversible proteasome inhibitor • Indication: FDA approved for multiple myeloma. Use for AMR is off label. • Dose: 1.3 to 1.5 mg/m2 IV day 1, 4, 8, 11. • Adverse effects: – Neuropathy, plt,  WBC, GI symptoms

• Cost ~$2000 per injection UW experience: used in kidney, liver and pancreas AMR Steroids + PP + IVIG + Bortezomib +/- ATG Everly et al, Transplantation, 2008 Djamali et al, Clinical Transplants, 2009 Sollinger et al, WTC Abstract 2010

Complement Inhibition Eculizumb • Recombinant humanized monoclonal IgG antibody produced from murine myeloma cells that inhibits the cleavage of C5 • Indication: PNH, atypical HUS • Blocks graft injury in presence of DSA, may suppress plasma cells. • Adverse effects: – Risk of neisseiria meningitis, need immunization

• Mayo monitored DSA, B & T flow CM, protocol Bx. • Dose: – 600 mg IV injection qw to q2w – Duration of therapy unknown – Cost $5000 for 300 mg vial

Monitoring during treatment • Graft function • Infection – Viral, bacterial, fungal

• Bone marrow suppression – Leukopenia, thrombocytopenia, anemia

• DSA • Immunosuppression • Repeat biopsy

Prevention • Identify who is at risk – Sensitized • Current PRA > 20%, Peak PRA > 50% • Black race, Female, retransplant

– + crossmatch – Certain disease states (SLE, PSC)

• Caution with minimizing immunosuppression • Monitor – DSAs, Biopsy, organ function

UW Kidney Transplant Rejection Protocols Suspicious Dex 50 mg IV + taper IA, IB

Dex 100 mg IV + taper

IIA, IIB, III

Dex 100 + taper + ATG

C4d< 50% +/Banff I

Early: ( 3m) Dex 50 mg + taper + IVIG 100 mg/kg weekly x 4wks

C4d> 50% +/Banff I

Early: Dex 100 mg + taper + TPE 3 to 5 treatments + IVIG 100mg/kg

Late: Dex 100 mg + taper + IVIG 100mg/kg x 4wks

C4d < 50% + Banff II or III

Dex 100mg/kg + taper + TPE 3 to 5 treatments + IVIG 100mg/kg + either ATG or Bortezomib

Conclusion • AMR can occur at any time • Biopsy confirmed diagosis • Due to preformed Ab, memory response or de novo Ab production • Causes vascular injury & fibrosis  to  long term graft survival • Can be recalcitrant to treatment  risk for infectious complications after treatment

Thank you!