Editing Blood transfusion (section)

=== Immunologic reaction ===
* [[Acute hemolytic transfusion reaction|Acute hemolytic reactions]] are defined according to Serious Hazards of Transfusion (SHOT) as "fever and other symptoms/signs of haemolysis within 24 hours of transfusion; confirmed by one or more of the following: a fall of Hb, rise in lactate dehydrogenase (LDH), positive direct antiglobulin test (DAT), positive crossmatch"<ref name=":1">{{Cite book|title = The 2014 Annual SHOT Report (2015)| vauthors = Bolton-Maggs PH, Poles D |publisher = SHOT|year = 2015|isbn = 978-0-9558648-7-2 |collaboration = Serious Hazards of Transfusion (SHOT) Steering Group|url = http://www.shotuk.org/wp-content/uploads/report-2014.pdf|access-date = 2016-01-21|archive-url = https://web.archive.org/web/20160127114949/http://www.shotuk.org/wp-content/uploads/report-2014.pdf|archive-date = 2016-01-27|url-status = dead}}</ref> This is due to destruction of donor red blood cells by preformed recipient antibodies. Most often this occurs because of clerical errors or improper [[ABO blood group system|ABO blood typing]] and crossmatching resulting in a mismatch in ABO blood type between the donor and the recipient. Symptoms include fever, chills, chest pain, back pain,<ref name="LauraDean"/> hemorrhage, [[tachycardia|increased heart rate]], shortness of breath, and [[hypotension|rapid drop in blood pressure]]. When suspected, transfusion should be stopped immediately, and blood sent for tests to evaluate for presence of hemolysis. Treatment is supportive. Kidney injury may occur because of the effects of the hemolytic reaction (pigment nephropathy).<ref name=":2">{{cite web|url = https://www.hhs.gov/ash/bloodsafety/2011-nbcus.pdf|title = The 2011 National Blood Collection and Utilization Survey Report|access-date = 21 January 2016|publisher = Department of Health and Human Services|archive-date = 19 March 2016|archive-url = https://web.archive.org/web/20160319015943/http://www.hhs.gov/ash/bloodsafety/2011-nbcus.pdf|url-status = dead}}</ref> The severity of the transfusion reaction is depended upon amount of donor's antigen transfused, nature of the donor's antigens, the nature and the amount of recipient antibodies.<ref name="LauraDean"/>
* [[Delayed hemolytic transfusion reaction|Delayed hemolytic reactions]] occur more than 24 hours after a transfusion. They usually occur within 28 days of a transfusion. They can be due to either a low level of antibodies present prior to the start of the transfusion, which are not detectable on pre-transfusion testing; or development of a new antibody against an antigen in the transfused blood. Therefore, delayed haemolytic reaction does not manifest until after 24 hours when enough antibodies are available to cause a reaction. The red blood cells are removed by macrophages from the blood circulation into liver and spleen to be destroyed, which leads to extravascular haemolysis. This process usually mediated by anti-Rh and anti-Kidd antibodies. However, this type of transfusion reaction is less severe when compared to acute haemolytic transfusion reaction.<ref name="LauraDean"/>
* [[Febrile non-hemolytic transfusion reaction|Febrile nonhemolytic reactions]] are, along with allergic transfusion reactions, the most common type of blood transfusion reaction and occur because of the release of [[cytokine|inflammatory chemical signals]] released by white blood cells in stored donor blood<ref name=":3" /> or attack on donor's white blood cells by recipient's antibodies.<ref name="LauraDean">{{cite book|vauthors=Laura D|title=Blood Groups and Red Cell Antigens|date=2005|publisher=National Center for Biotechnology Information|location=Bethesda, United States|url=https://www.ncbi.nlm.nih.gov/books/NBK2261/|access-date=4 October 2017|archive-date=25 March 2021|archive-url=https://web.archive.org/web/20210325083706/https://www.ncbi.nlm.nih.gov/books/NBK2261/|url-status=live}}</ref> This type of reaction occurs in about 7% of transfusions. Fever is generally short lived and is treated with [[antipyretic]]s, and transfusions may be finished as long as an acute hemolytic reaction is excluded. This is a reason for the now-widespread use of leukoreduction — the filtration of donor white cells from red cell product units.<ref name=":3" />
* [[Allergic transfusion reaction]]s are caused by IgE anti-allergen antibodies. When antibodies are bound to its antigens, [[histamine]] is released from [[mast cell]]s and [[basophil]]s. Either IgE antibodies from the donor's or recipient's side can cause the allergic reaction. It is more common in patients who have allergic conditions such as [[hay fever]]. Patient may feel itchy or having hives but the symptoms are usually mild and can be controlled by stopping the transfusion and giving [[antihistamine]]s.<ref name="LauraDean"/>
* Anaphylactic reactions are rare life-threatening allergic conditions caused by IgA anti-plasma protein antibodies. For patients who have [[selective immunoglobulin A deficiency]], the reaction is presumed to be caused by IgA antibodies in the donor's plasma. The patient may present with symptoms of fever, wheezing, coughing, shortness of breath, and [[shock (circulatory)|circulatory shock]]. Urgent treatment with [[epinephrine (medication)|epinephrine]] is needed.<ref name="LauraDean"/>
* [[Post-transfusion purpura]] is an extremely rare complication that occurs after blood product transfusion and is associated with the presence of antibodies in the patient's blood directed against both the donor's and recipient's platelets HPA (human platelet antigen). Recipients who lack this protein develop sensitization to this protein from prior transfusions or previous pregnancies, can develop thrombocytopenia, bleeding into the skin, and can display purplish discolouration of skin which is known as [[purpura]]. Intravenous immunoglobulin (IVIG) is treatment of choice.<ref name="LauraDean"/><ref>{{Cite book|title = Practical Transfusion Medicine| vauthors = Murphy M |publisher = Wiley-Blackwell|year = 2013|pages = 127–130|chapter = Post-transfusion purpura|edition = 4th| veditors = Murphy M, Pamphilon D, Heddle N }}</ref>
* [[Transfusion-related acute lung injury]] (TRALI) is a syndrome that is similar to [[acute respiratory distress syndrome]] (ARDS), which develops during or within 6 hours of transfusion of a plasma-containing blood product. Fever, hypotension, shortness of breath, and tachycardia often occurs in this type of reaction. For a definitive diagnosis to be made, symptoms must occur within 6 hours of transfusion, hypoxemia must be present, there must be radiographic evidence of bilateral infiltrates and there must be no evidence of left atrial hypertension (fluid overload).<ref name=":5">{{cite web |url=https://www.cdc.gov/nhsn/biovigilance/blood-safety/ |title=Blood Safety |publisher=National Healthcare Safety Network (NHSN), Centers for Disease Control and Prevention |date=July 2024 }}</ref> It occurs in 15% of the transfused patient with mortality rate of 5 to 10%. Recipient risk factors includes: end-stage liver disease, sepsis, haematological malignancies, sepsis, and ventilated patients. Antibodies to human neutrophil antigens (HNA)  and human leukocyte antigens (HLA) have been associated with this type of transfusion reaction. Donor's antibodies interacting with antigen positive recipient tissue result in release of inflammatory cytokines, resulting in pulmonary capillary leakage. The treatment is supportive.<ref>{{cite journal | vauthors = Kim J, Na S | title = Transfusion-related acute lung injury; clinical perspectives | journal = Korean Journal of Anesthesiology | volume = 68 | issue = 2 | pages = 101–5 | date = April 2015 | pmid = 25844126 | pmc = 4384395 | doi = 10.4097/kjae.2015.68.2.101 }}</ref>
* [[Transfusion associated circulatory overload|Transfusion associated circulatory overload (TACO)]] is a common, yet underdiagnosed, reaction to blood product transfusion consisting of the new onset or exacerbation of three of the following within 6 hours of cessation of transfusion: acute respiratory distress, elevated brain natriuretic peptide (BNP), elevated central venous pressure (CVP), evidence of left heart failure, evidence of positive fluid balance, and/or radiographic evidence of pulmonary vascular congestion.<ref name=":5" /> Patients with [[congestive heart failure]] or kidney disease are more susceptible to volume overload.  For especially vulnerable patients, a standard RBC unit could be split by sterile technique in the blood bank and administered over 8 hours instead of the standard 4 hours.  Plasma transfusion is especially prone to causing TACO because large volumes are usually required to give any therapeutic benefit.
* [[Transfusion-associated graft versus host disease]] frequently occurs in immunodeficient patients where recipient's body failed to eliminate donor's T cells. Instead, donor's T cells attack the recipient's cells. It occurs one week after transfusion.<ref name="LauraDean"/> Fever, rash, diarrhoea are often associated with this type of transfusion reaction. Mortality rate is high, with 89.7% of the patients dead after 24 days. Immunosuppressive treatment is the most common way of treatment.<ref>{{cite journal | vauthors = Kopolovic I, Ostro J, Tsubota H, Lin Y, Cserti-Gazdewich CM, Messner HA, Keir AK, DenHollander N, Dzik WS, Callum J | display-authors = 6 | title = A systematic review of transfusion-associated graft-versus-host disease | journal = Blood | volume = 126 | issue = 3 | pages = 406–414 | date = July 2015 | pmid = 25931584 | doi = 10.1182/blood-2015-01-620872 | doi-access = free }}</ref> Irradiation and leukoreduction of blood products is necessary for high risk patients to prevent T cells from attacking recipient cells.<ref name="LauraDean"/>