Prevalence of A2 and A2B Subgroups and Anti-A1 Antibody in Blood Donors in Jazan, Saudi Arabia

Muhammad Saboor; Amtuz Zehra; Hassan A Hamali; Amr Jamal Halawani; Abdullah A Mobarki; Aymen M Madkhali; Saleh Abdullah

doi:10.2147/IJGM.S272698

Prevalence of A₂ and A₂B Subgroups and Anti-A₁ Antibody in Blood Donors in Jazan, Saudi Arabia

Int J Gen Med. 2020 Oct 7:13:787-790. doi: 10.2147/IJGM.S272698. eCollection 2020.

Authors

Muhammad Saboor^{1

2}, Amtuz Zehra³, Hassan A Hamali¹, Amr Jamal Halawani¹, Abdullah A Mobarki¹, Aymen M Madkhali¹, Saleh Abdullah¹

Affiliations

¹ Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia.
² Medical Research Centre (MRC), Jazan University, Jazan, Saudi Arabia.
³ Basic Science Department, King Saud Bin Abdulaziz University, Al Ahasa Branch, Saudi Arabia.

Abstract

Purpose: A₂ and A₂B are rare phenotypes of the ABO blood group system. Some individuals with A₂ and A₂B may have anti-A₁ antibodies that may be clinically significant or insignificant. The aim of this study was to determine the frequency of A₂, A₂B phenotypes and anti-A₁ antibodies in blood donors in Jazan, Saudi Arabia. This study also evaluated the reactivity potential of anti-A₁ antibodies.

Materials and methods: Blood samples collected from 446 blood donors were typed for ABO (cell and serum grouping) and Rh D. Individuals with blood group A and AB were further subtyped by testing with anti-A₁ lectin. In addition to the serum grouping using A₁ red cells, A₂ and A₂B individuals were screened for the presence of anti-A₁ in their sera against A₁ red cells at 4°C, 22°C and 37°C to determine the thermal amplitude of the reacting anti-A₁ antibody (if present).

Results: Among A and AB, A₁ was the commonest phenotype (20.2%, n=90 out of 446) while A₁B was found to be 1.8% (n=8) among AB phenotype. A₂ and A₂B were found to be 2.2% (n=10) and 0.9% (n=4), respectively. Only one individual with A₂B blood type showed cold reactive anti-A₁ antibody, the strength of which was 32.

Conclusion: A₂ and A₂B were the rarest among ABO phenotypes in the studied population. Although rare, anti-A₁ antibody is not so uncommon. Care shall be taken during routine ABO grouping especially in cases of mix-field or weak positive reactions in A and AB phenotypes.

Keywords: ABO; Saudi Arabia; anti-A1; antibodies; blood groups; subgroups.