Title: INACTIVATION OF PATHOGENS IN BLOOD PRODUCTS
1INACTIVATION OF PATHOGENS IN BLOOD PRODUCTS
- Martin H. Ellis MD
- Hematology Institute and Blood Bank
- Meir Hospital
2OUTLINE OF THE TALK
- Transfusion transmitted infections (TTI) -the
scope of the problem - Means available to decrease incidence of TTI
- Pathogen inactivation
- Technologies available
- Clinical trial results
3Breakdown of transfusion hazards reported to
SHOT, 1996 to 2004
4Annual risk of TTI
Developing world U.K.
150 000 12 135 000 HIV
5 million 1935 000 HCV
16 million 1144 000 HBV
? 1641 000 HTLV-I
Lancet 2005652151
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6Blood-borne pathogensknown and screened by
testing
- Viruses
- HIV12
- HTLV III
- HBV
- HCV
- CMV (selected)
- West Nile virus (seasonal-US)
- Bacteria
- T. pallidum
- Protozoa
- T. cruzi (Chagas disease)
7Blood-borne pathogensknown but NOT screened by
testing
- Viruses
- EBV
- HHV-6, 7 8
- HDV
- Parvovirus B19
- Arboviruses (35 species!! including chikungunya)
- Coronavirus (SARS)
- Avian influenza
- Dengue hemorrhagic fever (Sept 2008)
- Bacteria (Gram , Gram -, anerobes)
- Protozoa (malaria, Babesia, Borrelia)
- Prions (vCJD)
8MEANS AVAILABLE TO DECREASE INCIDENCE OF TTI
- Donor selection
- Phlebotomy technique
- Diversion collection bag
- Laboratory testing
- Specialized filters (nanofiltration pores 15-40
nm) - PATHOGEN INACTIVATION
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10PATHOGEN INACTIVATION
- ADDITION OF VARIOUS ADDITIVES TO BLOOD PRODUCTS
TO INACTIVATE - - viruses
- - bacteria
- - protozoa
-
- INACTIVATION OF PRIONS
- NOT POSSIBLE AT PRESENT
11Pathogen InactivationComponent Considerations
- Stable components
- Plasma products
- Labile components
- Platelet units
- Red cell units
12FRESH FROZEN PLASMA
- Solvent / Detergent
- EC approved
- Methylene blue
- EC approved
- UVA light psoralen (amotosalen)
- - EC approved
- Riboflavin (vitamin B2)technology
- experimental
13Solvent / Detergent (S/D) plasma
- Solvent tri-n-butylphosphate
- Detergent triton X 100
- Active against LIPID enveloped viruses
- HBV, HCV, HIV, HTLV, EBV, CMV
- Not active against PROTEIN coated viruses
- Parvovirus B19, Hepatitis A virus
14S/D plasma the process
- FFP (single units or pheresis) thawed
- Pooling 2 500 donors/pool
- Incubation with S/D for 4 hrs _at_ 30C
- S/D extracted with vegetable oil and resin
chromatography - Pool is aliquoted into 200 cc units ? final
product is called POOLED PLASMA
15S/D plasma - problems
- Large pool size
- Increased risk for parvovirus B19 and HAV
transmission - - abortions/hydrops fetalis
- marrow aplasia in patients with hemolytic anemia
- problematic in immunocompromised patients
PARVOVIRUS B19
16S/D plasma - problems
- Bleeding in severe liver disease and liver
transplantation because of reduced levels of
?-2 antiplasmin increased fibrinolysis
(Transfusion 19993912271234) - Reduced levels of protein S (natural
anticoagulant) causes increased incidence of
venous thrombosis (in TTP patients) (Br J
Haematol 2003121778785)
REMOVED FROM U.S. MARKET
17S/D plasma - cost
- 200 000 / QALY (Quality adjusted life year)
- (EXPENSIVE!!)
Curr Opin Hematol Sept 2008
18Methylene Blue treated plasma(MB plasma)
- Binds guanosine residues of DNA/RNA
- Light of 590 nm wavelength activates the dye ?
genetic damage inactivation - In use in Europe (gt 3 million units transfused),
no adverse effects reported
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22MB plasma - quality
- Reduction in activity of labile clotting factors
of 10 30 - ( factors VIII, V and fibrinogen)
- May be associated with increase in transfusion
requirements of FFP and cryoprecipitate - ( 56 in a Spanish study ! Transfusion, Dec
2001)
23Psoralen treated FFP
- Photochemical treatment
- Used for single FFP units
- Psoralen forms adducts with DNA and RNA
prevents replication - Effective against lipid and non-lipid enveloped
viruses - gt 5000 units transfused in Europe no apparent
adverse effects
24PLATELETS
- UVA light psoralen (amotosalen)
- - EC approved
- Riboflavin (vitamin B2)technology
- experimental
25 PSORALEN TREATED PLATELET UNITS
- Inactivates bacteria (Gram Gram -),
viruses, protozoa - Suitable for use with buffy coat or pheresis
platelet units - Large randomized clinical trials in
thrombocytopenic patients have been conducted
EuroSPRITE and SPRINT
26SPRINT main features
Control Treated
Apheresis Apheresis Product
327 318 of pts
50 39 Platelet survival
16 000 11 000 Corrected count increment (/µL)
5 5.5 Red cell unit transfusion requirements
6.2 8.4 Platelet transfusion required
6.1 4.1 Bleeding WHO grade 3-4
plt0.05
Blood 2004
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28Clinical experience with INTERCEPT
- Licensed in Europe in 2002
- gt 60 000 transfusions in 11 countries
- No need for gamma irradiation (!)
- No requirement for bacterial testing, emerging
virus testing - No increase in platelet use overall
- Chikungunya outbreak in Reunion required rapid
deployment of system-satisfactory!
Consensus Conference on PI, US NIH, 2007
29RIBOFLAVIN TREATED PLATELET UNITS
- Vitamin B2 non-toxic, no need to remove
- Absorbs light and intercalates into DNA and RNA
- Causes strand breakage inhibits replication
- Clinical applications currently being investigated
30RED CELL UNITS
- Less progress compared to other components
- Psoralens do not work UVA light is absorbed by
Hemoglobin!
31RED CELL UNITS
- FRALES (Frangible Anchor Linker Effectors)
- 3 part molecules
- Activation is pH dependent
- Inactine
- Causes a stop signal that inhibits DNA RNA
polymerase activity - Unsuccessful clinically neoantigen formation
causing positive crossmatches
32Transfusion Med Rev 2008
33Ideal Pathogen Inactivation System
- Single units treated
- Absence of toxicity
- Safe in all patient populations (pregnancy,
neonates, renal failure, liver disease,
immunocompromised) - Reasonable cost
34Is pathogen inactivation a worthwhile enterprise?
- Real medical need?
- Technology and industry driven?
35It depends on What is acceptable risk?
36Blood Transfusion Circa 2005 2010 2015?
Transfusion 2000