6th EUROPEAN SYMPOSIUM ON RARE ANAEMIAS 1st Dutch-Belgian meeting for patients and health professionals

21st - 22nd November 2015

Amsterdam - The Netherlands

Sacha Zeerleder, MD PhD Academic Medical Center Amsterdam

s.s.zeerleder@amc.uva.nl

6th European Symposium on Rare Anaemias - 1st Dutch-Belgian meeting for patients and health professionals

Disclosures Company name Researc

h support

Employee

Consultant Stockholder Speakers bureau Advisory board Other

Viropharma X X X

Alexion x

6th European Symposium on Rare Anaemias - 1st Dutch-Belgian meeting for patients and health professionals

This talk is applicable for:

Definite Probable

Thalassemia’s x

Sickle cell disease x

Membrane disorders (e.g. sferocytosis)

x

Enzym defects (e.g. PKD, G6PD) x

PNH x

Other forms of hemolytic disease x

Sacha Zeerleder, MD PhD Academic Medical Center Amsterdam

s.s.zeerleder@amc.uva.nl

Evolutionary one of the oldest parts of the (innate) immune system

Complement: very old system

Jules Bordet

Traube & Gscheidlen 1874: Bacteria injected into circulation

are rapidly destroyed Ehrlich 1890: serum kills bacteria Bordet 1895: Serum containing anti-bacterial Ab + bacteria at 37C Lysis After heating (56C): No lysis

Paul Ehrlich

total ± 30 proteins in plasma and on cell membranes

Complement: historical perspective

Moritz Traube

Complement: keeps invaders away

Complement

Susceptibility to encapsulated bacteria (meningococcal disease, pneumococci)

Complement can harm

Complement

Susceptibility to autoimmune diseases (SLE), PNH, atypical HUS

Complement: injury and protection

Complement

Cascade of enzymatic reactions whereby each component

activates the next component in a fixed order by cleaving off

fragments

3 activation pathways

Cleavage fragments have biologic function

Complement system = cascade system

inactive

active

inactive

active

MAC (C5b-9)

C5b

C3b

C3

Complement system: an effector system

Alternative pathway

Low-grade hydrolysis

Opsonization (C3b, C4b)

Inflammation anaphylatoxins

(C3a, C5a)

MAC (C5b-9)

C5b

C3b

C3

Opsonization (C3b, C4b)

Inflammation anaphylatoxins

(C3a, C5a)

Three complement activation pathways

Alternative pathway

Classical pathway Lectin pathway

C4bC2a C4bC2a

Three complement activation pathways: regulation

C1-inhibitor

C4BP

Factor I

Factor H

Plasma inhibitors

MCP (CD46)

sCR1

DAF (CD55)

protectin (CD59)

Membrane inhibitors

Wouters & Zeerleder, Haematologica 2015

C3b

C3

Complement system: alternate pathway

Alternative pathway

Low-grade hydrolysis

Plasma

Cell surface

exogenous endogenous

Endogenous structures are protected by complement inhibitors/regulators

MAC complex (C5b-9)

C5b

C3b

C3

H2O Bb

C3b B

C3b

P

D

P

Classical pathway Lectin pathway

Bb

C3b B

C3b

B

DAA

CA

FI

Complement system

Decay accelerating activity (DAA) for C3 convertase (C3bB/C3bC3b) • Factor H (FH) • DAF (CD55) Cofactor activity for Factor I (FI): inactivates C3b • Factor H (FH) • Membrane cofactor protein

(MCP)

Wouters & Zeerleder, Haematologica 2015

Complement system- amplification loop

Amplification loop- regulation

Atypical HUS : Complement Factor H (CFH)

• Complement Control Protein repeats: CCP repeats (à 60 aa) • Mw~150 kD • Chromosome 1q32 • aHUS: 30% mutations in FH

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 NH2 COO

Recognition-site C3b:

• dissociation C3-convertase

(C3bB, C3bC3b)

• Cofactor for CFI (cleavage C3b)

Recognition-site surfaces:

• Basement membranes

• Endothelium

20% 60% Mutations

Kavanagah & Goodship 2010, Noris & Remuzzi, 2009, Richards et al 2007

FH mutation – renal damage

No complement deposition

complement deposition

Anti-C5 (Eculizumab)

Anti-C5

Greenbaum et al. 2013

AP: controlled by membrane bound regulators

MAC complex (C5b-9)

C5b

C3b

C3

Alternative pathway

Opsonization (C3b, C4b)

Inflammation anaphylatoxins

(C3a, C5a)

Classical pathway Lectin pathway

C4bC2a C4bC2a

MCP (CD46)

DAF (CD55)

protectin (CD59)

Membrane inhibitors

Wouters & Zeerleder, Haematologica 2015

Etn

Man

Man

Man Gluc

In

GPI-linked protein

PIGA -gen

CD alternative name function

CD 14 Pattern recognition

receptor (PRR) Receptor for

LPS

CD 16 Fc-gamma receptor IIIb Low-affinity receptor IgG

CD 24 Heat stable antigen Cell adhesion

molecule

CD 48 Signaling lymphocyte activation molecule 2

(SLAMF2)

Member Ig-superfamily

CD 52 Campath-1 Not entirely

clear

CD 55 Inhibition formation C3-

convertase Cell-adhesion

CD 59 Membrane inhibitor of

reactive lysis

Inhibition C9 polymerization

(MAC)

CD 66 CEA family Cell-adhesion

Membrane bound regulators are GPI- linked

Zeerleder, van Solingen & v. Wijk 2015

Alternate pathway: membrane-bound regulators

Alternate pathway: membrane-bound regulators

PNH: uncontrolled activation alternative complement pathway

C3b MAC C5b

PNH: uncontrolled activation alternative complement pathway

Anti-C5

Anti-C5

Hillmen et al. 2006

Complement inhibitors: a bright future

C1-inhibitor

C4BP

Factor I

Factor H

Plasma inhibitors

MCP (CD46)

sCR1

DAF (CD55)

protectin (CD59)

Membrane inhibitors

Wouters & Zeerleder, Haematologica 2015

Complement system in haematological diseases

3 pathways: classical, mannan-binding lectine and alternative pathway Effective effector system to fight “bugs” from outside Inadequate control of complement activation may be harmful - deficiency/dysfunction of complement regulators - Membrane bound vs fluid-phase (plasma) Diseases caused by inadequate control complement activation: • Atypical HUS among others mutation factor H • PNH deficiency of GPI-linked regulators (CD55/59)

Endothelial cell activation/damage

Thrombotic microangiopathic angiopathy (TMA)- aHUS

FD

FBb

FB

C3

Spontaneous hydrolysis

FBb

C3b C3b

FBb

C3b

FBb P

PF: positive feedback loop

FH/FI

CR1/MCP/DAF

FH/FI

Alternative C3 convertase

C3 C3b(H2O) H2O

C3b

C3 PF

FD

FB

C3b

CR1/MCP/DAF

Complement system: alternate pathway

Wouters & Zeerleder, Haematologica 2015

Atypical HUS

Hemolytic anemia

Thrombocytopenia

Fever

Neurological symptoms

Renal dysfunction

Defective plasmatic regulation of alternative

pathway (dysfunctional factor H)