Prevalence and Titre Levels of Anti- A and Anti- B Antibodies among Blood Group O Donors at Kenyatta National Hospital Blood Transfusion Unit, Kenya

Abstract

In many countries, blood group O is considered a universal donor; nevertheless, there have been reported cases of transfusion reactions due to transfusion of group O whole blood and its components in non O recipients. These adverse outcomes are attributed to high titres of naturally occurring immunoglobulin M (IgM) and immune immunoglobulin G (IgG) blood group antibodies in this donor blood. Antibody levels vary in diverse populations and are not known at the Kenyatta National Hospital (KNH) setting. This study aimed at determining the prevalence, and titre levels of IgM and IgG anti-A and anti-B antibodies amongst group O donors at Kenyatta National Hospital Blood Transfusion Unit. A cross-sectional study was adopted and carried out at KNH between February and April 2018. A sum of 233 group O donors took part in the study. A multi-stage convenience sampling method was used. A questionnaire was used to obtain demographics and specific known variables related to high antibody titre. Donor blood was collected and processed to obtain plasma which was afterwards titrated by the use of an immunohematology analyzer (Immucor Neo®) to detect IgM and IgG anti-A and anti-B antibody titres. Descriptive statistics was established on demographic variables. In assessing the relationship between high antibody titre and variables, Chi-square and Fisher exact tests were used. The blood donor population ages ranged from 18-58 years and the mean age was 29.3(SD ±8.7) years. The majority of them were male 183/233 (78.5%) with the most common age group was of 18-28 years consisting 122/233(52.4%). The prevalence of high titre among the group O donors was at76 % irrespective of antibody class (IgG and IgM) and specificity (anti-A and anti-B) using an antibody dilution cut off of ≥ 1:64. The prevalence of group O donors with titre ≥ 1:64 was 36% for IgM anti-A, 26.6% for IgM anti-B, 48.1% for IgG anti-A and32.2% for IgG anti-B. Age, gender, past transfusion history, and pregnancy were not related to high antibody titre. Nevertheless, and contrary to expectations, a higher antibody titre was detected among those who had not consumed yoghurt (P=0.03). This study sheds light on the significance of pre-transfusion ABO antibody titration at KNH. It is highly recommended that the use of group O donor blood be restricted to group O recipients. It should only be transfused to others groups in emergency times when a low antibody titre can be established.