Pathogen inactivation is a procedure of extinguishing potentially infective agents from constituents that threaten blood supply utilizing assorted methods.Such attack is made to do blood transfusion safe and minimise contamination.the mark of scuh methods is to damage the Deoxyribonucleic acid and RNA of the pathogen disenabling their reproduction in blood constituents whilst doing small or no harm to the cellular and plasma proteins.some of these methods are already in usage or undergoing clinical trails.the methods vary consequently with the type of blood constituent used.
Solvent detergent intervention was the first to be developed.It is largely used for pathogen inactivation in plasma.It utilizations organic detergent and dissolvers to demobilize lipid enveloped viruses such as HIV, HCV, EBV and CMV.it does that by interrupting the lipid envelope of the virus therefore forestalling replication.this technique is uneffective against non lipid enveloped viruses.Solvent-detergent ( SD ) consequences when a viricidal detergent and dissolver ( solvent 1 % tributyl phosphate and detersive 1 % Triton x100 for 4hrs at 30degress ) are incorporated into processing of plasma from pools of about 12000 Donar green goodss ( Barbara J.Bryant & A ; Harvey G.Klein ( 2007 ) pathogen inactivation: the unequivocal precaution for blood supply.Archieves of pathology anf research lab: may 2007, vol 131, No.5, pg719-733 ) .These chemical demands to eb removes afterwards, Tri-butuyl phosphate be oil extraction and Triton by chromatography absorption.This causes break in cells hence is non applicable for thrombocyte and ruddy cells.This method affects curdling factors by impacting proteins suc as alpha 2 antiplasmin and anticoagualant protein S.According to articles a new SD method Iraqi Intelligence Service developed for mini pools upto 10-12 units maximal recovery of curdling factors and avoiding big pooling of plasma.
Another effectual method used for plasma is Nanofilteration.This method is used to filtrate viruses based on their size.it uses a screening method being 15 to 40 nanometers in size efficaciously filtrating smaller viruses.Unlike SD this method removes both enveloped and non enveloped viruses and even viruses smaller than the pores size.also effectual in taking prion.the effectivity of this method depends on temperature, force per unit area, flow rate of filteration and ratio of protein voulume to filtrate area.This method has been documented to demo doing really small harm to the protein features leting recovery of 90-95 % of protein activity.
Another utile method for plasma is methylene blue in combination with seeable light.methylene bluish attaches to the viral nucleic acid which is so exposed to UV light.This inactivates most enveloped virus in the.This method is non utile in demobilizing non enveloped viruses, Protozoa, bacteriums and other intracellular viruses.the procedure of freeze and melt amendss the leukocytes which makes the virus more vulnerable to this treatment.MB method has said to impact the plasma proteins and besides curdling factors scuh as factor I and factor VIII.According to most articles MB treated plasma cause a slow coagulum formation apart from that does non do inauspicious transfusion reactions although long term surveies on its toxicity and carcinogenicity has non been carried out. ( AuBuchon 2011, McCullough 2007 )
UVC visible radiation and gamma radiation is aso a utile method applied for plasma and platelet.this method is carried out in combination with photosensitizers.different wavelength visible radiations are uses which causes alterations in nucleic acerb structure.Not does this lone amendss the pathogen but it besides affects the proteins.despite this drawback it has been reported tha Uv intervention inactivates most of the viruses including HIV completely.As with other antecedently mentioned methods this method besides affects the effectivity of curdling factors although no clinical test for this has been performed.UV light tends to damage thrombocyte, increase their metabolic rate and increase its activation during storage ( AcBouch 2011 )
Amotosalen method is used for both thrombocyte and plasma products.It uses a man-made porsalen compound, Amotosalen hydrochloride ( S-59 ) .This compound when exposed to UVA light affects DNA and RNA construction by organizing cross nexus bonds between them.formation of these bonds prevents reproduction and transcription.a broad assortment of pathogengets inactivated utilizing this method such as virueses ( HIV, CMV, HPV ) , protozoa ad bacteria.It besides modifies the Deoxyribonucleic acid leucocytes doing inactivation of T lymphocytes.There this method has said to be utile in forestalling transfusion reactions associated to leukocytes such as host V transplant disease and home base associated transfusion reaction ( Canellini, Waldugel, Andregg, Tisset 2010 ) amotosalen allows less harm to platelet morphology as it uses UV visible radiation for a short period of clip.Platelet dressed ore dressed ore is reduced and resuspened in approximately 70-75 % thrombocyte additives such as Na chloride.acetate.citrate and phosphate followed by add-on of amotosalen, incubation for 5 proceedingss and so exposure to UVA light.Byproducts are removed while thrombocyte is transferred to another bag incorporating S-59 and farther incubated for 4-16 hours with agiataion. ( McCullough 2007, AcBouch 2010 ) As per diary articles this is the lone method for which complete trails has been carried out demoing really small difference to the normal thrombocyte standard.treatment of plasma utilizing this method is really similer to that of thrombocyte, difference being no thrombocyte additives are added.this can be kept for upto 1 twelvemonth when frozen at -18 degress.the merchandise is known as fresh frozen plasma.Plasma protein and curdling factors activites is affected to a really minimum level.Cryoprecipitate can besides be produced utilizing this method although no clinical trails has been carried out.no toxicity degrees has been reported utilizing this method.
Riboflavin/UV visible radiation is another method employed in pathogen inactivation of platelet.riboflavin a of course happening compound found in nutrients. when exposed to UV visible radiation it causes oxidization of guanosine bases.this oxidization causes breakage of the DNA strands to an extent that is beyond repair.this alteration in construction prevents the Deoxyribonucleic acid from retroflexing and transcribing.most of the pathogens gets inactivated including intracellular and cell associated HIV, bacterium and protozoa.platelet/plasma under goes Uv intervention in a temperature controlled environment in a bag incorporating Ribofalvin.As with the former method it doesnaa‚¬a„?trequire remotion of its by-product as it is of course occurring.In comparing the metabolic alterations in Amolostalen is more marked compared to riboflavin, take downing the ATP degrees due to mitochondrial based energy production. ( AcBouch 2011 ) There is more glycolosis doing activation of platelet.no important harm is caused to the curdling factors although trails are still underway.If the storage exceeds 5 yearss platelet viability gets affected.This applies to both Psoralens and riboflavin.UV light method. ( McCullough 2007 )
Thionine is a phenolthiazine dye that can be used in combination of UV visible radiation to demobilize pathogens in platelets.Advantage of this method being it besides uses UVB visible radiation which increases the effectivenss of pathogen inactivation although clinical trails are still underway.as with other methods there is a small alteration in home base morphology and its chemical composing.
The most ambitious of all is pathogen inactivation in ruddy blood cells due to increased opportunities of haemolysis and lessening endurance of RBC.Techologies for pathogen decrease of ruddy blood cells are still under development such methods include S-303, PEN 110, Riboflavin/UV visible radiation, Dimethylene blue and flexible phtosenzitizer dyes.
S-303 ( FRALE- fragible ground tackle linker extender ) is an alkalyting agent that targets the nucleic acids of viruses, parasites, bacteriums and Protozoa without depending on visible radiation for activation.S-303 is positively chared which attaches to the negative nucleic acid of the pathogen doing hydrolysis forestalling replication.RBC maps appears to be normal utilizing this method whislt in vivo maps are more than 75 % .despite this as with all methods there is a drawback of this method too.there is formation of antibodies against the RBC treated with S-303 although this doesnaa‚¬a„?t create any clinical jobs.
A similar method PEN 110 which is an INACTINE compound is shown to demobilize a assortment of viruses, Protozoa and even mycoplasma.Inactine a positively charged ethlyeneamine binds to negatively bear down phosphate.the activation caused by this bonding causes the nucleic acid strands to interrupt preventing replication.leucocytes are removed before add-on of PEN 110 followed by incubation at room temperature.the cells are so washed and preservative solution is added.This can be stored for 42 days.As with S-303 there is no formation of antibodies against the treated RBC.there is minimal haemolysis and ruddy cell antigens are non affected to a great extent.According to journal articles non plenty clinical trails has been run to govern out its immunoreactivity and immunogenicity.
Riboflavin/UV visible radiation is similar to that used in thrombocyte pathogen inactivation.Varying wavelength of light ( 280-350 nanometer ) is used which non merely inacitvtes pathogens but besides leucocytes.RBC recovery is non shorted nor is there formation on of antibodies.This technique Army Intelligence still undergoing trail. ( AcBouch 2011, McCullough 2007 )
Dimethylmethlene blue is a proactive dye that has a high affinity ot nucleic acid.when it undergoes seeable visible radiation it causes inactivation of DNA and RNA in RBC.compared to other methods this method affects RBC to a great extent doing hemolysis.Rbc is washed with normal saline and resuspended in an linear solution which is so incubated with dimethymethlene blue before illumination.this affects RBC intregrity although no clinical tests has been reported for this method.
The last method T mentioned is the use of photosenziter dyes such as Thioprylium ( TP ) and Thiozole orange.these dyes attach and perforate viral membrane impacting their mirid bugs and nucleic acids under a certain wavelength of light.. non merely does this cut down photochemical harm to RBC but tends to demobilize legion intracellular viruses ( HIV ) , many gram positive and gram negative bacteria.A drawback for utilizing this method is that it amendss RBC membrane during phototreatment.it causes potassium escape from RBC to a great extent.According to articles big graduated table surveies has non been carried out utilizing this method.