Biology of Disease

Figure 6.1Some blood products: (A) plasma

(B) erythrocytes and (C) platelets. Courtesy of the

Manchester Blood Transfusion Service, UK.

Reason Examples

Possibility of transmitting infectious agents in leukocytes human immunodeficiency virus (HIV)

cytomegalovirus (CMV)

prion proteins responsible for variant

Creutzfeldt-Jakob disease (vCJD)*

Possibility of immunizing against leukocyte antigens sensitization to major histocompatibility

antigens

Increased risk of graft versus host disease (GVHD) with

whole blood

in immunosuppressed or immunodeficient

individuals

Possibility of inducing febrile reactions post-transfusion

(nonhemolytic febrile reactions)

caused by cytokines released from

leukocytes in storage

*In 2003 a recipient of blood taken from a healthy donor who developed vCJD, also died of vCJD 6 years after

transfusion. Other evidence since that time suggests that it is possible to transmit vCJD with leukocytes (see also

Chapters 2and 15 ).

Table 6.1Reasons for leukodepleting blood before transfusion

6.3 The Discovery of the Blood Group Systems

It has been known since the seventeenth century that the transfusion of blood
between individuals could have rapid and fatal consequences. Fortunately, in
1900 Landsteiner (1868–1943) discovered that individuals could be classified
into different groups depending on the characteristics of their erythrocytes
and the presence of specific antibodies in their plasma to erythrocyte anti-
gens. These discoveries laid the foundations for the routine and safe therapeu-
tic transfusion of blood. Landsteiner drew blood from a number of individuals
and separated the erythrocytes from the plasma. He then mixed together all
possible combinations of erythrocytes and plasma from these individuals
together and showed that only certain combinations resulted in the clump-
ing or agglutination of the erythrocytes (Figure 6.2). These patterns of agglu-
tination showed that there were different blood groups, which Landsteiner
named A, B and O. In 1902 von Decastelo (1872–1960) and Sturli (1873–1964)
discovered a fourth blood group which he called AB. It became clear that fatal
blood transfusions resulted from incompatible blood being transfused and

THE DISCOVERY OF THE BLOOD GROUP SYSTEMS

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Figure 6.2The agglutination of erythrocytes by

antierythrocyte antibodies.