The Blood Group A Genotype Determines the Level of Expression of the Blood Group A on Platelets But Not the Anti-B Isotiter

Abstract

Background: The extent of expression of the blood group A on platelets is controversial. Further, the relation between platelets' blood group A expression and the titers of isoagglutinins has not been thoroughly investigated, so far. Methods: We evaluated the relation between the genotype with platelets' blood group A and H expression estimated by flow cytometry and the titers of isoagglutinins. Results: The A expression varied between genotypes and within genotypes. However, the expression in A₁ was stronger than in all other genotypes (p < 0.0001). An overlap of expression levels was apparent between homozygous A₁A₁ and heterozygous A₁ individuals. Still, The A₁A₁ genotype is associated with a particularly high antigen expression (p = 0.009). Platelets' A expression in A₂ versus blood group O donors was also significant (p = 0.007), but there was again an overlap of expression. The secretor status had only little influence on the expression (p = 0.18). Also, isoagglutinin titers were not associated with genotypes. Conclusion: To distinguish between A₁ and A₂ donors may reduce incompatible platelet transfusions and therefore be favorable on platelet transfusion increment. Clinical data are needed to support this notion.

Prevalence of type I sensitization to alpha‐gal in forest service employees and hunters: Is the blood type an overlooked risk factor in epidemiological studies of the α‐Gal syndrome?

“…Limitations of our study are that blood type characteristics were obtained from serum by examining isoagglutinins, blood type‐associated IgM and IgG antibodies, with defined erythrocytes in a haemagglutination test. Titers of isoagglutinins are independent from the genetically determined expression of blood type antigen and can be influenced by various individual and environmental factors . False‐positive results can occur due to irregular antibodies in the serum or unspecific agglutination and false‐negative results due to low isoagglutinins titers in the serum or degradation of blood type antigen on test erythrocytes due to cell aging .…”

“…Titers of isoagglutinins are independent from the genetically determined expression of blood type antigen and can be influenced by various individual and environmental factors . False‐positive results can occur due to irregular antibodies in the serum or unspecific agglutination and false‐negative results due to low isoagglutinins titers in the serum or degradation of blood type antigen on test erythrocytes due to cell aging . Therefore, this test does not carry out the same specificity and sensitivity as blood typing with erythrocytes.…”