How similar are the different ethnic groups of the people

Antibodies against rare blood group characteristics

Other blood type systems

There are particularly large differences in the Duffy blood group system (Fy), because this surface protein of the erythrocytes is not expressed at all in many Africans. Since they have the characteristics Fya and Fyb absent, these people are protected from tertian malaria.

There are almost no red cell concentrates without Duffy characteristics from Caucasian blood donors. Patients Fya- and Fyb-negative, but can also be Fyb- be positively transfused if the Fy antigen is expressed in the endothelium (usually Fyb without Fya, rarely the other way around). The latter can be determined by molecular biology using leukocyte DNA. On Fya-positive EC should be avoided in these patients in order to prevent general Fy immunization.

In Africans there is also a special feature in the MNS system that is not found in Caucasians: The antigens S and s are missing in around 1%, mostly in combination with a missing antigen U from the MNS blood group system. The associated antibody can cause hemolysis, which is why compatible transfusions should be sought.

There is an antigen in the Kell blood group system in Africans that is practically unknown in Caucasians: the antigen Jsa occurs with a frequency of up to 20%; up to 1% of African patients is Jsb-negative. These people don't necessarily make antibodies, but they do make anti-Jsb is available, the EK supply is expensive. The same applies to the k-negative type, which is rare among Caucasians (0.2%) and practically nonexistent among Africans. For people from the Middle East, up to 1.8% can be k-negative[2].

Finally, the antigen Yt is missinga from the Cartwright blood type system, which Caucasians commonly express, in 2.4% of Middle Eastern patients[2]. Antibodies against this characteristic can become clinically relevant in the course of antigen-dissimilar transfusions.

In summary, it can be stated that the probability of the formation of antibodies is relatively high; Data on the incidence of immunizations are in the range of about 3 to 8%[5]. It would be wrong, however, to attribute these numbers primarily to ethnic diversity and increasing migratory pressure. Data from erythrocyte concentrates that have been produced using the latest technology show above all a clear dependence of the observed incidences on the number of antigens considered.

The immunization and formation of blood group antibodies has always been the most common side effect after blood transfusions and therefore requires strict adherence to the guidelines issued by the German Medical Association and the Paul Ehrlich Institute for the collection of blood and blood components and for the patient regardless of the patient's ethnic background Use of blood products.