410 Microbes and You 



the report published by Moss. A universal system of blood 

 group designations has since been adopted, and letters of the 

 alphabet are assigned in place of numbers for the various blood 

 groups. The two first letters of the Greek alphabet, alpha (for 

 anti- A ) and beta ( for anti-B ) , are employed to designate the anti- 

 bodies found in blood sera. To indicate the relationship between 

 the Jansky, Moss, and universal systems of blood grouping, the 

 following table is presented. 



Table 10 

 SUMMARY OF BLOOD GROUPING SYSTEMS 



JANSKY MOSS UNIVERSAL EFFECT OF ANTISERA ON RED BLOOD CELLS 



I IV O Not agglutinated by either anti-A or anti-B 



serum . 



Agglutinated by anti-A serum. 

 Agglutinated by anti-B serum. 

 Agglutinated by anti-A and anti-B sera. 



The discovery of iso-agglutinins in human blood was not put 

 to practical use until during the first world war, when many 

 persons were dying as the result of transfusions with heterologous 

 (mixed) blood. With the necessities of war serving as a stimulus, 

 blood grouping came into its own, and the use of donors whose 

 blood was compatible with that of the recipient resulted in suc- 

 cessful transfusions. While the distribution of blood types varies 

 with different races and with different locations throughout the 

 world, the distribution in the United States is approximately 45% 

 type O, 40% type A, 10% type B, and 5% type AB. Published figures 

 do not agree exactly, but these percentages are representative. 



BLOOD TRANSFUSIONS 



In order to understand why transfusions are successful in some 

 cases and disastrous in other patients, it is necessarv to appreciate 

 that the donor's blood should not contain erythrocytes for which 

 the recipient possesses specific circulating antibodies. The follow- 

 ing table should make this point clear bv indicating which blood 

 type persons are able to receive blood from other individuals. 



