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EtymologyEtymology

The name The name ""white blood cell“ iswhite blood cell“ is derived derived from the fact that after centrifugation of a from the fact that after centrifugation of a blood sample, the white cells are found in blood sample, the white cells are found in the buffy coat, a thin, typically white layer the buffy coat, a thin, typically white layer of nucleated cells between the sedimented of nucleated cells between the sedimented red blood cells and the blood plasma. The red blood cells and the blood plasma. The scientific term leukocyte directly reflects scientific term leukocyte directly reflects this description, derived from Ancient this description, derived from Ancient Greek λευκό (white), and κύτταρο (cell). Greek λευκό (white), and κύτταρο (cell).

Leukocyte content of whole blood Leukocyte content of whole blood averages two billion ( 2 x10averages two billion ( 2 x109 9 ) leukocytes ) leukocytes per 500 mL of whole blood. per 500 mL of whole blood.

During blood component preparation : During blood component preparation : • 90% of leukocytes fractionate with the red 90% of leukocytes fractionate with the red

blood cells (RBCs). blood cells (RBCs).

• 8% is retained within Platelet concentrates.8% is retained within Platelet concentrates.

• 2% are present in the plasma before 2% are present in the plasma before freezing.freezing.

Leukocyte reduction can be achieved by Leukocyte reduction can be achieved by various techniques, including : various techniques, including :

CentrifugationCentrifugation Leukocyte filtrationLeukocyte filtration SedimentationSedimentation WashingWashing Freeze-thawingFreeze-thawing ApheresisApheresis

Leukocyte Reduction Leukocyte Reduction FiltersFilters

GenerationPore SizeMechanismPurpose

First170–260 um Screen filter No leukocyte filtration;

“standard” blood filter

Second20–49 um Screen filter

Micro-aggregate filter;

leukocyte filtration,

90%

ThirdNot applicable Adhesion filter

Adsorption filter;

leukocyte filtration

99.9%

LeukocyteLeukocyte

FilterFilterss

Adverse Effects Associated Adverse Effects Associated with Donor Leukocytes with Donor Leukocytes

1.1. Nonhemolytic febrile transfusion reactionsNonhemolytic febrile transfusion reactions2.2. Transmission of leukocyte-associated viruses Transmission of leukocyte-associated viruses

cytomegalovirus cytomegalovirus 3.3. AlloimmunizationAlloimmunization4.4. Immunomodulatory effectsImmunomodulatory effects5.5. Cancer recurrenceCancer recurrence6.6. Postoperative infectionsPostoperative infections7.7. Transfusion storage time for red blood cellsTransfusion storage time for red blood cells8.8. Transfusion storage time for plateletsTransfusion storage time for platelets9.9. Transfusion-related acute lung injuryTransfusion-related acute lung injury10.10. Transfusion-associated graft-versus-host diseaseTransfusion-associated graft-versus-host disease

1. Febrile Nonhemolytic 1. Febrile Nonhemolytic Transfusion ReactionsTransfusion Reactions

Definition :Definition : as a temperature increase of 1°C as a temperature increase of 1°C after an allogeneic blood transfusion.after an allogeneic blood transfusion.

Cause :Cause : alloantibodies in the recipient’s alloantibodies in the recipient’splasma against antigens present on donorplasma against antigens present on donorleukocytes and/or platelets leukocytes and/or platelets

Incidence:Incidence: 0.5%0.5% in patients receiving a first transfusion in patients receiving a first transfusion60%60% in Chronically transfused patients in Chronically transfused patients

2. Transmission of 2. Transmission of leukocyte-associated viruses leukocyte-associated viruses

(e.g.cytomegalovirus)(e.g.cytomegalovirus)

Transfusion-associated CMV infection is a significant Transfusion-associated CMV infection is a significant

cause of morbidity and mortality in immuno-compromised cause of morbidity and mortality in immuno-compromised

patients and especially in organ transplant recipients.patients and especially in organ transplant recipients.

After either kidney or liver transplants, more than 60% of After either kidney or liver transplants, more than 60% of

patients develop antibodies against CMV.patients develop antibodies against CMV.

3. Platelet Refractoriness 3. Platelet Refractoriness and Alloimmunizationand Alloimmunization

Alloimmunization can reduce the clinical Alloimmunization can reduce the clinical effectiveness of platelet transfusions by effectiveness of platelet transfusions by 50%. Especially prevalent among those : 50%. Especially prevalent among those :

-- Patients receiving pooled random donor Patients receiving pooled random donor

platelet concentrates.platelet concentrates.

-- Who are Pregnant. Who are Pregnant.

4. Immunomodulation and 4. Immunomodulation and Postoperative Infectious Postoperative Infectious

ComplicationsComplications

Contaminating leukocytes in RBC transfusions Contaminating leukocytes in RBC transfusions

might be responsible for down-regulation ofmight be responsible for down-regulation of : : Natural-killer (NK) cell activity, Natural-killer (NK) cell activity, T cell proliferationT cell proliferation T lymphocyte antitumor activityT lymphocyte antitumor activity CD-4 helper to CD-8 suppressor ratioCD-4 helper to CD-8 suppressor ratio Lymphocyte blastogenesisLymphocyte blastogenesis

5. Cancer Recurrence 5. Cancer Recurrence

An association between allogeneic blood An association between allogeneic blood transfusion and colorectal cancer recurrence after transfusion and colorectal cancer recurrence after surgery.surgery.

Blood transfusions in colorectal surgery patients Blood transfusions in colorectal surgery patients have been reported to increase cancer recurrence have been reported to increase cancer recurrence by 37%also have been associated with increased by 37%also have been associated with increased recurrence of breast, lung, kidney, prostate, recurrence of breast, lung, kidney, prostate, stomach, cervical, laryngeal, soft tissue, and bone stomach, cervical, laryngeal, soft tissue, and bone malignancies.malignancies.

6. Postoperative infections6. Postoperative infections

Transfusion of blood components Transfusion of blood components containing bacteria may lead to potentially containing bacteria may lead to potentially fatal sepsis. fatal sepsis.

Cause :Cause : inadequate skin preparation inadequate skin preparation before venipuncture.before venipuncture.

Common pathogens :Common pathogens : include Gram- include Gram-

negative endotoxin producing organisms negative endotoxin producing organisms such as Yersinia enterocolitica, such as Yersinia enterocolitica, pseudomonas and enterobacter pseudomonas and enterobacter

66 . .Postoperative Postoperative infectionsinfections

Optimal storage time before filtration to Optimal storage time before filtration to allow for maximal leukocyte ingestion of allow for maximal leukocyte ingestion of bacteria appeared to be between 2 and 12 bacteria appeared to be between 2 and 12 hours. hours.

The beneficial effect of leukocyte reduction The beneficial effect of leukocyte reduction may lie in removal of leukocytes containing may lie in removal of leukocytes containing ingested bacteria.ingested bacteria.

Decrease ATP.Decrease ATP. Glucose consumption.Glucose consumption. Increase lactate and kIncrease lactate and k++ production. production. The presence of leukocytes in blood The presence of leukocytes in blood

components reduces glucose availability.components reduces glucose availability. leukocyte lysis leads to release of leukocyte lysis leads to release of

cytokines that reduce RBC survival.cytokines that reduce RBC survival.

7. Transfusion storage 7. Transfusion storage time for red blood cellstime for red blood cells

Decreases in pHDecreases in pH Increases in glucose consumptionIncreases in glucose consumption Lactate productionLactate production Lactic dehydrogenase releaseLactic dehydrogenase release Platelets stored with leukocytes express Platelets stored with leukocytes express

decreased quantities of glycoprotein Ib decreased quantities of glycoprotein Ib (GPIb) receptor, resulting in a bleeding (GPIb) receptor, resulting in a bleeding disorders.disorders.

8. Transfusion storage 8. Transfusion storage time for plateletstime for platelets

9. Transfusion-related 9. Transfusion-related acute lung injuryacute lung injury

Stored blood contains micro-aggregates of Stored blood contains micro-aggregates of

degenerated leukocytes, platelets and fibrindegenerated leukocytes, platelets and fibrin

These micro-aggregates have been associated These micro-aggregates have been associated

with pulmonary insufficiency due to with pulmonary insufficiency due to

agglutination of donor leukocytes by recipient agglutination of donor leukocytes by recipient

antibodies.antibodies.

C/P :C/P : severe dyspnea, non-cardiogenic severe dyspnea, non-cardiogenic

pulmonary edema.pulmonary edema.

10. Transfusion-associated 10. Transfusion-associated graft-versus-host disease graft-versus-host disease

(GVHD)(GVHD)GVHD is a potentially lethal condition.GVHD is a potentially lethal condition.

Cause :Cause : donor T lymphocytes. donor T lymphocytes.

Mechanism :Mechanism : immunocompromised recipients, host defense immunocompromised recipients, host defense mechanisms fail to suppress viable transfused donor mechanisms fail to suppress viable transfused donor lymphocytes, which engraft within the recipient’s marrow, lymphocytes, which engraft within the recipient’s marrow, ultimately resulting in death.ultimately resulting in death.

Occurrence : Occurrence :

1.1. when the donor and recipient share an HLA haplotype. when the donor and recipient share an HLA haplotype.

2.2. Use of directed-donor blood from first degree relatives. Use of directed-donor blood from first degree relatives.

Prophylaxis :Prophylaxis : gamma-irradiation. gamma-irradiation.

Few side effects have been reportedFew side effects have been reported1.1. Hypotension : due to release of bradykinin like Hypotension : due to release of bradykinin like

vasoactive substance esp. in patients receiving vasoactive substance esp. in patients receiving ACEI prolong intravascular half life of ACEI prolong intravascular half life of bradykinin : by decreasing bradykinin bradykinin : by decreasing bradykinin degradation.degradation.

2.2. Complement activation and formation of Complement activation and formation of platelets aggregateplatelets aggregate

2%-8% decrease in potency of cellular 2%-8% decrease in potency of cellular components of blood. components of blood.

Adverse Effects of Adverse Effects of Leukocyte ReductionLeukocyte Reduction

3.3. Red eye syndrome ( allergic conjunctivitis). Red eye syndrome ( allergic conjunctivitis).

- Erythema 100%.- Erythema 100%.

- Periorbital edema 16%- Periorbital edema 16%

- Eye pain 15%- Eye pain 15%

- Itching - Itching

Symptoms resolve 48 hours but erythema may Symptoms resolve 48 hours but erythema may require up to 3 weeks.require up to 3 weeks.