Transcript Acquired idiopathic TTP

Moschowitz ‘ Disease
Galila Zaher
MRCPath
Case Presentation
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20 years old Saudi patient
Easy fatigability
Easy bruising
Afebrile
Systemic examination normal
Anaemia & thrombocytopenia
Blood film
High urea & creatinin
Clinical course
Abdominal US
 Auto-immune profile
 Seizures
 Plasma pharesis
 Normal platelets count
 Renal dialysis
 Relapse
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Thrombotic Thrombocytopenic
Purpura
Thrombotic thrombocytopenic purpura
(TTP) is characterized by
 Microangiopathic hemolytic anemia
 Thrombocytopenia
 Microvascular thrombosis causes
variable degrees of tissue ischemia and
infarction
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VWF Biochemistry
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VWF monomers synthesized in EC
Monomers linked into multimers
Multimers constructed in megacaryocytes & EC
Stored in alpha granules & weibel-palade bodies
ULVWF entangled to sub-endothelial collagen
Bind to platelets GP1b-IX –V and activated plt
GPIIb-IIIa  adhesion and aggregation
Moake et al 1982
VWF Biochemistry
 Activation, immobilization and spreading
 Recruit more VWF and more platelets
 A disintegrin and metalloprotease with eight
thrombospondin -1-like domain ADAMTS
 Metalloprotease cleaves ULVWF in A2
domain
 Impaired degradation of VWF by deficiency
of metalloprotease
Tsai 1996
 Characterization of ADAMTS and elicidation
of its cDNA and gene structure 2001
ADAMTS 13
Encoded on chromosome 9q34
Produced mainly in liver
Activator : Zn and Ca requiring protein
Inhibitors : metal chelators & EDTA
Substrate : VWF
Plasma activity 50-178%
 Half-life 2-3 days
Patho-physiology
TTP favored by conditions that combine
 Increased VWF level (late pregnancy)
 Decreased ADAMTS13 activity
 Two-hit model could explain
substantial variation in age at which
patients with inherited TTP develop
symptoms.
Platelet-rich Microvascular
Thrombi
 Wide spread of intravascular thrombosis
 Organ ischemia :Renal, Cerebral
 Blood flows through turbulent area of
partially occluded by platelet aggergates
 Schistocytes
 High LDH correlates with severity of
ischemia
Clinical Presentation
Pentad
 Thrombocytopenia (increased marrow
megakaryocytes)
 Microangiopathic hemolytic anemia (MAHA)
 Renal failure (50%)
 Neurologic abnormality (25%)
 Fever
 Thrombocytopenia , schistocytes & elevated
LDH
 Nonspecific symptoms: weakness, abdominal
pain, nausea, vomiting, and diarrhea
 Median duration of symptoms prior to
diagnosis was 6 days
Oklahoma TTP-HUS Registry
Types Of TTP
 Congenital TTP
 Acquired idiopathic TTP
 Secondary TTP
Congenital Familial TTP
 Moschowitz ‘ Disease
 Rare : Autosomal recessive
 Homozygous mutations in both ADAMTS13 alleles
 Both parents showing 50% of activity
 Infancy or childhood
 Severe ischemic brain lesions by MRI
 ADAMTS13 < 5% of normal plasma
 Almost always have ULVWF multimers
 Response to FFP infusion is rapid :Prophylactic FFP q23 weeks avoid relapses
Conditions Associated
Bone marrow transplantation
Pregnancy & Postpartum
Drugs
Autoimmune disorders
TBI
Kidney, liver, heart, or lung transplant
Drug-associated TTP
 Acute immune-mediated or dose-related toxic
 Most common cause of immune-mediated TTP
 Quinine ( isolated thrombocytopenia)
 Ticlopidine (TTP and HUS)
 Clopidogrel (TTP and HUS)
 Mitomycin C- Cyclosporine
 Tacrolimus (FK506)
 Discontinuation or dose adjustment is sufficient
 Trial of plasma exchange :efficacy is uncertain
Acquired idiopathic
Adults and older children
 Sever ADAMTS 13 deficiency :acute
episodes
 IgG autoantibody produced transiently
 Return to normal upon recovery
 Mortality rate 13%
 Worse prognosis :Prolonged courses &
more frequent complications
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HUS
 Children, usually >5 years old
 Bloody diarrhea
 E.coli O157:H7
 Shiga toxin
 Acute renal failure
 Thrombocytopenia and MAHA
 Mortality is 3-5%
 Normal plasma ADAMTS13 activity
 Plasma exchange treatment is rarely considered
Laboratory Tests
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Anemia
Thrombocytopenia
Blood film : (Schistocytes > 1% of total RBCs)
High LDH (hemolysis and leakage from
ischemic tissue)
High bilirubin
DCT negative
High urea and ceriatnin
PT , APTT, fibrinogen & D-dimers :normal
Diagnosis
No “gold standard” for diagnosis
 ADAMTS13 activity
 Auto-antibodies against ADAMTS13
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Clinical Applications
Diagnosis
 Discrimination of TTP from HUS
 Discrimination of congenital and
acquired
 Estimating risk of relapse
 Monitoring therapeutic efficacy of
plasma exchange or plasma infusion.
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Furlan
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NP VWF as substrate
Test plasma is activated by barium chloride
Mix over night in presence of 1.5M urea
Separated by SDS agarose gel electophoresis
Followed by immunoblotting.
Excellent resolution leader
Very sensitive
Reproducible
Requires several days
Bohm et al
Test plasma is incubated with
recombinant substrate
 Separated by SDS polyacrelamide gel
 Quantitate residual VWF using RIPA
 Short incubation
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Immunoassay Assay
Residual VWF binding to collagen
after its degradation
 ELISA simple
 Fast few hours
 Less sensitive and less precise
 Problems with reproducibility
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Low Levels Of ADAMTS
PLiver disease
DIC
Chronic metabolic conditions &
inflammatory conditions
Uremia
HIT
Pregnancy third trimesters
Newborn
Healthy controls :levels 20-50% and
none < 10%
Management
Untreated almost always fatal (90%)
FFP
Byrnes and Khurana 1977
Cryo-supernatant contain ADAMTS
Tsai 1998
Solvent/detergent-treated plasma
contain ADAMTS
Tsai and Lian and Furlan 1998
Plasma pheresis
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Plasma exchange reduced MR from 90%- 25%
Remove circulating ULVWF multimer-platelet
strings
Remove circulating auto-antibodies against
ADAMTS13
Infusion of FFP or cryosupernatant , SD or
methylene blue/light-treated plasma
Response rate 80%–90%
T1/2 of infused ADAMTS13 activity is 2 days
Prompt and complete response : no further
therapy
Risk For Relapse
 Severe
ADAMTS13 deficiency
 Idiopathic TTP auto-Abs
 Non following SCT
 No relapse following drug toxicity
 No relapse who had a prodrome of
bloody diarrhea
Oklahoma TTP-HUS Registry
Management Of Relapse
Most relapses occur within the first
year
Suboptimal
response
or
:steroids
Sever neurologic defect
:immunosuppressive treatment
relapse
Spleenectomy: eliminates autoantibodyproducing B cells
Acquired idiopathic TTP
Lower titers better responses
 High titer inhibitor wore prognosis
 Inconsistent response to steroids and
other immunosuppressive agents
 Rituximab or cyclophosphamide
 Removal of autoantibody-producing
cells by splenectomy.
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Pregnancy And TTP
During pregnancy ,postpartum 70%
around time of delivery
 Pre-eclampsia/HELLP :3rd trimester or
following delivery, HT , protinurea &
Spontaneous postpartum recovery
 Observation for several days after
delivery
 Acute, severe multi-organ failure
:prompt plasma exchange
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TTP Following BMT
 Post allogeneic : 2-76%
 Post autologous : 0-27%
 Mortality rate : 0-93%
 DD : Renal and neurotoxicities of GVHD
 Cyclosporine and Tacrolimus
 Clinically suspected TTP: efforts to diagnose & treat
GVHD and sepsis & delay a decision for plasma exchange
 ADAMTS13 activity :normal
 No response to plasma exchange
HIV
 Typical TTP
 Acquired autoantibody to ADAMTS13
 Rapidly fatal course
 Plasma exchange :one plasma volume once daily
 Glucocorticoids auto-antibodies to ADAMTS13
Thank
you
Central Venous Catheter
Insertion
 Deaths
 Cardiac arrest with near-death
 Hemorrhage
 Pneumothrax
 Pericardial tamponade
 Allergic reactions
 Severe hypotension and hypoxia
 Fatal sepsis
ADAMTS13 Absent
Clinical Presentation
ADAMTS13 mutations
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Presentation in
infancy/childhood
ii.
Disease presentation delayed
Familial TTP; chronic relapsing TTP
Autoantibodies against ADAMTS13
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Transient
ii.
Recurrent
iii.
Thienopyridine-associated
Acquired idiopathic TTP
Single episode
Recurrent (intermittent) TTP
Ticlopidine/clopidogrel-TTP
ADAMTS13 transient production or
survival (?) defect
Acquired idiopathic TTP (?)
Pregnancy
Pregnancy-associated TTP
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Tsai
Plasma samples incubated with guanidine HCl-treated VWF X1hr
Products separated by SDS–polyacrylamide gel electrophoresis
Immunoblotting
Obert et al
Plasma samples incubated with recombinant VWF overnight
Degraded VWF fragments detected by two-site immunoradiometric
assay
Performed in hospital laboratory
High-throughput method
Gerritsen et al Functional assay
Preferential binding of HMWt forms of VWF to collagen.
Plasma treated with EDTA to abolishes the VWF-cleaving activity.
Dialyzed against the buffer and used as substrate.
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Recombinant protein as ADAMTS13 substrate
E coli culture
Direct assay for measuring ADAMTS13
product generation
More accurate
Protease-free VWF.
Substrate tagged with two different
molecules makes it easy to modify the
detection of product.
One potential disadvantage : GST-VWF73-H is
not a natural substrate
Sensitivity And Specificity
Specificity: Severe deficiency
(<5% ) is specific
Sensitivity
remains
questionable 66%- 100% Tsai
and Lian.
Levy et al identified 12 gene
mutations
Parameter
Finding
Neurologic findings
None
0
Confusion, lethargy, behavioral changes
1
Focal neurologic deficits, convulsions, stupor, coma
2
None
0
BUN > 30 and < 70 mg/dL and/or creatinine ? 1.5 mg/dL and <
2.5 mg/dL, and/or proteinuria > 2 g per day and/or hematuria
1
BUN >= 70 mg/dL and/or creatinine >= 2.5 mg/dL and/or dialysis
2
> 100,000 per L
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20,000 – 100,000 per L
1
< 20,000 per L
2
> 12 g/dL
0
9-12 g/dL
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< 9 g/dL
2
Renal function impairment
Platelet count at presentation
Hemoglobin level at presentation
Points
Differential Diagnosis
• Thrombotic thrombocytopenic purpura (TTP)
• Immune thrombocytopenia purpura (ITP)
• Autoimmune hemolytic anemia
• Hemolytic uremic syndrome (HUS)
• Pregnancy, eclampsia
• Disseminated intravascular coagulation (DIC)
• Septicemia with DIC
• Systemic lupus erythematosus (SLE)
• Scleroderma
• Paroxysmal nocturnal hemoglobinuria (PNH)
Comparison of the features of TTP
and hemolytic uremic syndrome (HUS)
Feature
TTP
HUS
Age
Peak incidence at 40 years
Childhood
Gender
Female
Equal
Epidemic
No
Yes
Re-occurrence
Common
Rare
Link to E. coli 0157:H7
Occasional
Yes
Renal failure
Uncommon
Common
Neurologic
Common
Uncommon
Thrombocytopenia
Severe
Moderate to severe
Organ involvement
Multiple
Limited to kidney