Blood Groups and Blood Transfusion Dr Stuart Laidlaw Haematology Royal Hallamshire Hospital

Red blood cells Provide intravascular volume and O2 carrying capacity. Transfusion of red cells can be life-saving in situations of acute intravascular volume loss, e.g. trauma, surgery

Red blood cells Although red cells have a limited life-span, transfusion to another individual is a form of tissue transplantation, with similarities to kidney, heart and bone marrow transplantation Compatibility between donor and recipient is vital or rejection will occur

Red Cells Carry on the surface of their membrane many different proteins which differ between individuals These are the red cell antigens Inherited Over 400 different systems of red cell antigens Only 2 very important: ABO and Rhesus

ABO blood group system 4 blood groups: A, B, AB and O O is recessive, so O = 0,0 A= AA or AO, B=BB or BO, AB= AB O= 45%, A= 40%,B=12%, AB= 3%

ABO blood group system ABO unusual antigens: carbohydrate, not protein Naturally occuring antibodies from age 6 months IgM antibodies in plasma, don’t cross placenta IgM antibodies fix complement to C9, so transfusion reactions very severe

ABO blood group Can type cells as A, B or AB, using antibodies: anti-A and anti-B. If react with neither =group O Can type serum as double check O serum will contain anti-A and anti-B AB serum will not contain any antibody A will contain anti-B, B will contain anti-A

Rhesus blood group system Complex series of C,D and E antigens D/d by far most important D is a null gene, no protein product, so no anti-d possible D is dominant, so D = DD or Dd 15% population dd = d = d negative

Rhesus blood group system Women who are rhesus negative (dd) have babies that carry paternal antigens, such as D. If mother exposed to D red cells will make IgG anti-D Anti-D crosses placenta and haemolyses babies red cells: can result in in-utero death and need for in-utero blood transfusion

Rhesus blood group It is so vital that women of childbearing age are not exposed to wrong rhesus type blood that everyone receives rhesus, as well as ABO, compatible blood. All women have rhesus blood type determined at each conception. Anti-D given to D negative mothers to prevent sensitisation

Other blood groups Many in number Infrequent problem Only likely to have been sensitised if had previous blood transfusion (occasionally by pregnancy) Can cause major problems with finding compatible blood

Group and Save Determine ABO group: cells and serum Determine Rh D status, using two different reagents Screen serum for presence of preformed antibodies to any blood group

Cross match Specifically determine compatibility between donor red cells and recipients serum Very important if known antibodies or multiple previous transfusions If group and screen neg X 2 may be unnecessary, use electronic cross-match

Indications for transfusion Hypovolaemia due to loss blood Severe anaemia with symptoms due to inadequate oxygenation of tissues Anaemia that cannot be corrected by bone marrow function

Indications for transfusion Not indicated for iron deficiency or B12/ folate deficiency. Not indicated for minor blood loss, especially if fit and healthy (transfusion trigger = 8 g/dl) Not indicated for asymptomatic anaemia

Hazards of transfusion Blood is tissue from another individual Transfusion is potentially fatal, although used properly can, and does save lives

Early hazards ABO incompatibility reaction – can be rapidly fatal Fluid overload, pulmonary oedema Febrile reactions, urticarial reactions, occasionally life threatening respiratory failure Bacterial and malerial infection

Late hazards Rh D and other antibody sensitisation Delayed transfusion reaction Viral infection: Hepatitis B, C, HIV ? Prion infection: nvCJD Iron overload: cardiac, hepatic and endocrine damage

Alternatives to transfusion Treat anaemia pre-op Use transfusion trigger Stop anti-platelet and anti-coagulant drugs Consider intra-operative cell salvage and re- infusion

Alternatives to transfusion Consider pre-and post- operative erythropoietin Consider individual pre-donation of red cells Currently no universally available alternatives to blood ?O2 carrying solutions, ? Artificial/ recombinant haemoglobin polymers

Other components Blood is not only red cells Also platelets and plasma Plasma can be used as it is, or fractionated to produce concentrates of specific components, e.g. factor VIII or IX White cells only rarely used, as antibiotics so potent!

Fresh frozen plasma Plasma frozen within 6 hours of collection Contains all the coagulation proteins and inhibitors Used if massive transfusion and dilutional coagulopathy, in liver disease and DIC

Cryoprecipitate Rich in fibrinogen Used in DIC and massive transfusion if specific lack of fibrinogen

Platelets Correct bleeding due to thrombocytopenia Work for lack of production or perippheral consumption Not useful if deficiency is due to immune anti-platelet antibody

Albumin Useful if oedema due to lack oncotic pressure in liver disease or nephrotic syndrome Use currently declining rapidly

Anti-D globulin Collected from people deliberately sensitised to D Used to prevent Rh D disease in Rh d women in pregnancy, after childbirth, miscarriage, abdominal trauma in pregnancy and TOP

Intravenous immunoglobulin Pooled immunoglobulin Used for immunodeficiency, congenital or acquired Used in some auto-immune diseases