Doyeun Oh

Department of Internal MedicineCHA University School of Medicine

Hemolytic uremic syndrome

Disclosures forDoyeun Oh

Research Support/P.I. No relevant conflicts of interest to declare

Employee No relevant conflicts of interest to declare

Consultant No relevant conflicts of interest to declare

Major Stockholder No relevant conflicts of interest to declare

Speakers Bureau No relevant conflicts of interest to declare

Honoraria No relevant conflicts of interest to declare

Scientific Advisory Board No relevant conflicts of interest to declare

Pathogenesis of STEC-HUS and aHUS

Differential diagnosis of TMA

Guidelines to manage STEC-HUS and aHUS

Contents

01

02

Initial recognition of HUS 

Microangiopathic hemolytic anemia (MAHA)Hb

A B

C D

04

Needs for correct diagnosis and treatment of HUS

Clinical features are similar or overlapped among

thrombotic microangiopathies.

Pathogenesis and clinical outcome with plasma

therapy is different.

Complement inhibitor can dramatically change the

outcome of aHUS.

05

Definition and terminology

Thrombotic microangiopathy (TMA): A pathology that results in thrombosis in capillaries and arterioles, due to an endothelial injury characterized by hemolytic anemia and thrombocytopenia

Hemolytic uremic syndrome (HUS) : a disease characterized by hemolytic anemia, acute kidney failure, and a low platelet count, without severe ADAMTS13 deficiency

Shiga toxin producing E coli- associated hemolytic uremic syndrome (STEC-HUS): HUS caused by infectious agents which produce Shiga toxin

Atypical HUS (aHUS): A heterogeneous group of diseases that have a TMA associated with some degree of acute kidney injury (AKI), not associated with other forms of TMA

Complement –mediated TMANoris M and Remuzzi G. N Engl J Med 2009;361:1676-87George JN and Nester CM. N Engl J Med 2014; 371:654-666Loirat C, et al. Pediatr Nephrol 2016;31:15-39

Classification of HUS

Loirat C, et al. Pediatr Nephrol 2016;31:15-39

STEC-HUS

S. pneumoniae-HUS, Influenza A / H1N1-HUS

Alternative complement pathway dysregulation (Genetic, Acquired)-HUS

Cobalamin C defect-HUS

DGKE mutation-HUS

Unexplained (idiopathic) HUS

HUS with coexisting disease/condition (secondary HUS)

TMA

STEC‐HUS

aHUS

Secondary TMATransplantationInfectionPregnancy, Eclampsia, preeclampsia, HELLPDrugs Autoimmune disease (SLE, scleroderma)Malignancy and chemotherapyMalignant hypertensionGlomerulopathy

TTP

USS

TTP : thrombotic thrombocytopenic purpuraUSS : Upshaw-Schulman syndrome

06

Endothelial damage Platelet activation

Hemolysis

Acute kidney injury

STEC-infection

Complement dysregulation

Coagulation activation

Microcirculatory platelet-rich thrombus formation

Pathogenesis of HUS

07

90% of HUS

3-7% of E. coli or enterotoxin producing organism (S. dysenteriae) infection

Shiga toxin or Shiga-like toxin (Stx); two types, Stx-1 and Stx-2

O157:H7, O26:H11/H-, O104:H4, O157:H-, O145:28/H-, O103:H2/H-, O111:H8/H, O121, O113. (O, lipopolysaccharide Ag; H, flagellar Ag)

Shiga-toxin binds to the globotriaosylceramide (Gb3) receptor in the cell membrane, internalizes and induces cell death by inhibiting protein synthesis. Gb3 receptors are highly expressed in kidney, brain and gut than other tissues. Children has more Gb3 than adults.

Shiga-toxin upregulates the expression of E-selectin, ICAM-1, VCAM-1 facilitates leukocyte activation and endothelial injury.

Shiga-toxin upregulates the expression of P-selectin and induce the formation of ULVWF and platelet activation and thrombosis.

Salvadori M, et al. World J Nephrol 2013;2:56-76Jokiranta TS. Blood 2017;129:2847-56

Pathogenesis of STEC‐HUS

08

Gb3

Stx-Gb3 binding

Endocytosis

Retrograde traffic

Inhibition of tRNA-ribosome bindingGolgi

ER

Valerio E, et al. Toxins 2010;2:2359-410

Cytosol

Infectious enterocolitis

Stx- induced renal damageEndothelial damageTF-induced fibrin formationComplement activation

Stx : Shiga toxinGb3 : globotriaosylceramide

StxStx

bloody diarrhea renal failure

Gb3

Stx Stx

Shiga toxin producing E. Coli infection

09

5-10% of HUS

50-60% has genetic abnormalities.

Genetic mutations (autosomal dominant or recessive) or autoantibodies against regulatory proteins in the complement system

Dysregulation of alternative complement pathway causing uncontrolled excessive activation of complement system is the major cause of aHUS. It results in endothelial injury, leukocyte activation, platelet activation followed by thrombosis, thrombocytopenia, hemolysis, and renal failure.

Noris M and Remuzzi G. N Engl J Med 2009;361:1676-87Jokiranta TS. Blood 2017;129:2847-56

Pathogenesis of atypical HUS

11

Classical and lectinpathways

Alternative pathway(C3 tick-over)

C3 convertase(C4b2a)

C3 convertase(C3bBb)

C3

C3b(C5-convertase)

C5(activation)

MAC C5-9(formation)

Factor HFactor I

MCPTHBD

MAC: Membrane attack complex

MCP: Membrane cofactor protein

THBD: thormbomodulin

12

Noris M, et al. Clin J Am Soc Nephrol 2010;5: 1844–1859

Complement gene  abnormalities in patients with aHUS

13

661 2 3 4 5 7 8 9 10

3-10% of cases in children Functional deficiency of factor H Related with homozygous deletion of CFHR

Noris M and Remuzzi G. N Engl J Med  2009;361:1676‐87Jozsi M, et al. Blood. 2008;111:1512‐1514Sinha A, et al. Kidney Int. 2014;85:1151‐60

N-terminal C-terminal

Factor H autoantibody

611 12 13 14 15 17 18 19 2016

14

Noris M and Remuzzi G. Semin Nephrol. 2017 Sep;37(5):447-463Jokiranta TS. Blood 2017;129:2847-56

Gene Frequency in aHUS, %

CFH 24-28

CFHR1/3 homozygous deletion 3-10

MCP 5-9

CFI 4-8

CFB 0-4

C3 2-8

THBD 0-5

Combined  mutations 3‐5

DGKE 0‐3

Plasminogen NA

Factor XII NA

15

Genetic abnormalities in patients with aHUS

The pathogenesis of STEC-HUS is infection.

The major pathogenesis of aHUS is dysregulation of

complement system caused by genetic abnormalities or

autoantibody development.

Summary

16

TMA

STEC-HUS

TTP

TMA

ADAMTS13

MAHA Thrombocytopenia Acute kidney injury Hypertension

Neurologic disturbances

Respiratory disturbances

GI disturbances

Existence of triggers

Poor response to PEX

18

Initial recognition of aHUS 

Multiple hits are necessary for aHUS to manifest, including a trigger, mutations, and at-risk haplotypes in complement genes. Incomplete penetrance of mutations is a feature in the pathogenesis of aHUS. Mutations are predisposing rather than directly causal in the development of aHUS.

19Kavanagh D. and Goodship THJ, Hematology Am Soc Hematol Educ Program. 2011;2011:15-20

Multiple hits are necessary for aHUS to manifest

Infection

Drugs

Vaccination

Autoimmune disease

Pregnancy

Malignancy or cancer chemotherapy

Transplantation

Noris M and Remuzzi G. N Engl J Med 2009;361:1676-87Kavanach D, et al. Seminars Nephrol 2013;33:508-30 20

Triggers of aHUS 

Fremeaux-Bacchi, et al. Clin J Am Soc Nephrol 2013;8: 554–562 21

aHUS patients’ characteristics  at onset

The diagnosis of aHUS is made by

excluding other types of TMA by

(1) ADAMTS13 activity >10%

(2) no evidence of STEC-HUS

(3) no secondary TMA (coexisting disease)

22

Diagnosis of aHUS 

Transplantation Infection Pregnancy, Eclampsia, preeclampsia, HELLP Drugs Autoimmune disease (SLE, scleroderma) Malignancy and chemotherapy Malignant hypertension Glomerulopathy These patients may have also aHUS-risk genetic variants.

Kabanach D, et al. Semin Nephrol 2013;33:508-30Campistol JM, et al. Nefrologia 2013;33:27-45Cataland SR, et al. Blood 2014;123:2478-84Scully M, Goodship T. Br J Haematol 2014;164:759-66

Secondary TMA (coexisting diseases)

23

ELISA, Radial immunodiffusion or Western blot assay (C3, C4, CFH, antibody against CFH, CFI, CFB),Flow cytometry (MCP) Anti-CHF antibody test is the only assay urgently required during the acute phase because a positive result raises additional treatment option. Normal activity cannot exclude aHUS.Overlapping results in both TTP, STEC-HUS and aHUS

Gavriilaki E, et al. Blood 2015;125:3637-46 Kavanach D, et al. Clin Am Soc Nephrol 2007; 2:591-6Mannucci Cataland Johnson S, et al. Pediatr Nephrol 2014;29:1967-78Loirat C, et al. Pediatr Nephrol 2016;31:15-39

Detection of complement dysregulation:Serologic diagnosis 

24

RFLP and sequencing, next generation sequencing, copy number variation and multiplex ligation-dependent probe amplification.It is helpful for the correct diagnosis and predict the outcome of aHUS, especially for the assessment of the optimal duration of treatment and the risk of post-renal transplantation recurrence.DNA testing is not recommended as an upfront diagnostic test not only because it is time consuming but also because several patients have no identifiable mutation.

Gavriilaki E, et al. Blood 2015;125:3637-46 Kavanach D, et al. Clin Am Soc Nephrol 2007; 2:591-6Mannucci Cataland Johnson S, et al. Pediatr Nephrol 2014;29:1967-78

25

Detection of complement dysregulation:Genetic diagnosis

Modified HAM test

Quantitative hemolytic assay coupled with RFLP

In vitro activity assay

Skin biopsy

Investigational assay of atypical hemolytic uremic syndrome

26Gavriilaki E, et al. Blood 2015;125:3637-46 Yoshida Y, et al. PLoS One 2015;10:e124655Heinen S, et al. Mol Immunol 2013;54:84-8Magro CM, et al. Am J Dermatopathol 2015;37:349-56

Clinical suspicion is the first step to diagnosis aHUS.

TTP can be excluded by ADAMTS13 activity >10%.

STEC-HUS can be excluded by the demonstration of Shiga toxin in

stool.

The diagnosis of aHUS is made by excluding TTP, STEC-HUS and

secondary TMA (coexisting disease).

Screening for complementary abnormalities by serology is useful

for the diagnosis of aHUS but their concentrations are not

consistently abnormal.

Genetic screening for complementary abnormalities is most

informative but not mandatory for the diagnosis of aHUS.27

Summary

aHUS is often misdiagnosed as TTP or STEC-HUS, all of which show

common clinical features. However, the pathogenesis and response rate to

plasma exchange differ between syndromes . Eculizumab is a life saving

drug in many cases of aHUS. Delayed treatment of aHUS can cause death

or end-stage renal disease. Therefore, the early differential diagnosis of

aHUS from other forms of TMA is very important for its appropriate

management.

Guidelines facilitate the standardized management of aHUS and

accelerate the detection and clinical trials of patients with aHUS.

European pediatric guidelines , British guidelines, Japanese guidelines

Needs for guidelines on aHUS

28

TMA

Supportive care

PEXADAMTS13

Supportive care is the mainstay of therapy.

Fluid and electrolyte control, blood pressure control, red blood cell transfusion, hemodialysis..

Antibiotics: controversial effects Quinolone and trimehoprim induced Stx production, but azithromycin was effective..

Plasma exchange (PEX): controversial effects Because Stx is detectable in the circulation only very early in illness and because Stx- induced

endothelial injury are preceded the development of HUS, the pathogenetic rationale of PEX in

STEC-HUS is lacking.

Eculizumab: controversial effects

Page AV, Liles WC. Med Clin N Am 2013;97:681-95 30

Management of STEC‐HUS

Excellent outcome

Full recovery in > 80%

End-stage renal disease: less than 5%

Death: less than 5%

Complication and mortality is higher in old age adults.

Page AV, Liles WC. Med Clin N Am 2013;97:681-95

Prognosis

31

Supportive care is the mainstay of therapy.Fluid and electrolyte control, blood pressure control, red blood celltransfusion, and hemodialysis are necessary..

Antibiotics should be avoided in children with STEC-HUS..

The benefit of therapeutic plasma exchange is controversial and it should be avoided when STEC-HUS is confirmed.

Eculizumab is not recommended in STEC-HUS.

No clinical benefit has been found with therapeutic anticoagulation, administration of fresh frozen plasma or glucocorticosteroids. and their use in STEC-HUS is not recommended.

Page AV, Liles WC. Med Clin N Am 2013;97:681-95Igarashi T, et al. Clin Exp Nephrol 2014;18:525-57

Recommendations for the treatment of STEC‐ HUS

32

Scully M, Goodship T. Br J Haematol 2014;164:759-66Fremeaux-Bacchi V, et al. Clin J Am Soc Nephrol 2013;8:54-62

A half of patients with aHUS treated with supportive care

and plasma therapy had died or reached ESRD in 3 years.

Eculizumab is the treatment of choice as first line

treatment.

33

Management of aHUS

Plasma exchange (PEX) : 1.5 plasma volume Plasma infusion: 10-20ml/Kg Replacement of complement and elimination of inhibitors. Evidence from retrospective case studies Not effective in patients with MCP mutation because MCP is not

circulating but a anchored protein in cell membrane. Complete hematologic and renal recovery rates are lower than 50%.

Mortality and progression to ESRD are high. Complications: anaphylaxis, hypotension, hypervolemia, central

venous access obstruction Empirically recommended only in the case with good response or

when eculizumab is not available.

Campistol JM, et al. Nefrologia 2013;33:27-45Loirat C, et al. Semin Thromb Hemost 2010;36:673-81Noris M, et al. Clin J Am Soc Nephrol. 2010;5(10):1844-1859 Caprioli J, et al. Blood. 2006;108(4):1267-1272 34

Plasma therapy on aHUS

High rate of recurrence (up to 50%) Living donor kidney transplantation is contraindicated due

to high rate of recurrence. Eculizumab is effective to treat and prevent the recurrence

of aHUS in kidney transplantation.

Franchini M. Clin Chem Lab Med 2015;53:1679-88

Kidney transplantation in aHUS

35

Complement factor H, B, C3 and I are synthesized in the liver.

Results of surgery are improving. Isolated or combined kidney and liver transplantation may

be an option for the treatment of patients having aHUS without access to eculizumab treatment.

Nester CM, et al. Mol Immunol 2015;67:31-42Franchini M. Clin Chem Lab Med 2015;53:1679-88

Liver transplantation in aHUS

36

A humanized monoclonal antibody directed against the

complement protein C5 that inhibits terminal complement

activation.

Successfully used to treat patients with aHUS.

Controversial effects on typical HUS

Nurnberger J, et al. N Engl J Med 2009 29;360:542-4.Zuber J, et al. Am J Transplant 2012;12:3337-542. Lapeyraque AL, et al. N Engl J Med 2011;364:2561-3Menne J, et al. BMJ 2012;345:e4565Legengdre CM et al. N Engl J Med 2013;368:2169-81

Eculizumab (Soliris®)

37

38

C3

C5

Lectin Pathway Alternative PathwayClassical Pathway

Eculizumab

Tissue injury, TMA (?)

Natural Inhibitors:Factor H, I, MCP,CD55

Caprioli J, et al. Blood. 2006;108(4):1267-1272Noris M, et al. Clin J Am Soc Nephrol. 2010;5(10):1844-1859 Legengdre CM et al. N Engl J Med 2013;368:2169-81Fakhouri F, et al. Am J Kidney Dis. 2016 Jul;68(1):84-93Greenbaum LA, et al. Kidney International (2016) 89, 701–711

More than 50%

Less than 20%

ES

RD

and

Dea

th P

atie

nt (%

)

PEX/PI Eculizumab

39

Legengdre CM et al. N Engl J Med 2013;368:2169-81

Trial 1(n=17)

Trial 2(n= 20)

Complete TMA response 11 (65%) 5(25%) TMA event free 15 (88%) 16 (80%)Platelet normalization 14 (82%) NALDH normalization 13(82%) 19 (95%)Hb improvement by ≥ 2g/dL 11 (65%) 9 (45%)eGFR improvement by ≥ 15ml/min/1.73m2 8 (47%) 1 (5%)

40

Eculizumab is effective in aHUS

Fakhouri F, et al. Am J Kidney Dis. 2016 Jul;68(1):84-93Greenbaum LA, et al. Kidney International (2016) 89, 701–711;

Pediatric aHUS(n=22)

Adult aHUS (n= 41)

Complete TMA response 14 (64%)  30 (73%) 

TMA event free 21 (95%)  37 (90%)

Platelet normalization 21 (95%)  40 (98%)

LDH normalization 18 (82%) 37 (90%)

Hb improvement by ≥ 2g/dL 15 (68%) 25 (61%)

eGFR improvement by ≥ 15ml/min/1.73m2 19 (86%) 22 (54%)

Eculizumab is a safe and effective treatment in patients with aHUS: outcomes by 26 weeks of treatment 

41

Complement system is responsible for immunity against infections. Immunity against N. meningitis depends on the lytic terminal complement complex.

Eculizumab use is susceptible to meningitis and hemophilus infection.

Vaccination 2 weeks prior to ecculizumab is required. Antibiotic treatment with vaccination can be started in the

case that treatment with eculizumab cannot be delayed. Neither vaccines nor antibiotic prophylaxis guarantee full

protection against infections. Patient/family/caregiver education on signs of infection is necessary.

Loirat C, et al. Pediatr Nephrol 2016;31:15-39

Prophylaxis of infections before eculizumab

42

Indicated in anti-CFH autoantibody Combined with PEX Steroid, cyclophosphamide, RTX, MMF, azathioprine

Franchini M. Clin Chem Lab Med 2015;53:1679-88Sinha A, et al. Kidney Int. 2014;85:1151-60

Management of aHUS with anti‐CFH antibody: immunosuppressive treatment

43

Eculizumab should be considered as a first-line treatment for patients with symptomatic aHUS

All patients who are clinically suspected of having aHUS should be offered a trial of PEX and/or plasma infusions if eculizumab is not available

Live-related renal transplantation alone should be avoided in cases of aHUS

All patients receiving eculizumab should receive a meningococcal vaccination or antibioprophylaxis prior to receiving the first dose of eculizumab

Loirat C, et al. Pediatr Nephrol 2016;31:15-39Kato H, et al. Clin Exp Nephrol 2016;20:536-43Cheong HI, et al. J Kor Med Sci 2016;31:1516-28Taylor CM, et al. Br J Haematol. 2010;148:37-47Campistol JM, et al. Nefrologia. 2015;35:421-47

Recommendations for the treatment of  aHUS 

44

HUS is highly recommended to care in the hospital by

multidisciplinary approach.

Supportive care including plasma exchange is the main treatment of

HUS and should be initiated until the differential diagnosis is

clarified.

The benefit of therapeutic plasma exchange is controversial and it

should be avoided when STEC-HUS is confirmed.

Eculizumab is recommended as a first-line treatment for patients

with symptomatic aHUS.

45

Summary

HUS is a heterogeneous syndrome characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury.

The pathogenesis of STEC-HUS is infection and the major pathogenesis of aHUS is dysregulation of complement system.

Diagnosis of STEC-HUS can be made by the demonstration of Shiga toxin in the stool.

Diagnosis of aHUS can be made by excluding TTP, STEC-HUS and secondary TMA.

HUS is highly recommended to care in the hospital by multidisciplinary approach.

Supportive care including plasma exchange and hemodialysis is the main treatment of HUS and should be initiated until the differential diagnosis is clarified.

The benefit of therapeutic plasma exchange is controversial and it should be avoided when STEC-HUS is confirmed.

Eculizumab is recommended as a first-line treatment for patients with symptomatic aHUS.

46

Conclusions

2020 APSTH Gwangju, KOREA  

September 3 ‐5, 2020

ขอบคุณสาํหรับการฟัง