PREVALENCE OF α AND β-HAEMOLYSIN AMONG GROUP “O” BLOOD DONORS

ABSTRACT

Routine screening for haemolysins is not performed in our blood banks despite the increased incidence of cross-reacting anti-A (α-haemolysin) and Anti-B (β-haemolysin) among Blood group “O” individuals. This study aimed to determine the prevalence and haemolytic significance of α and β-haemolysin in our voluntary group “O” donor population in Benin City. This study was a cross-sectional study done by selecting randomly qualified group “O” donors in Benin City. Blood grouping was done using commercial anti-sera kits from Rapid Labs Limited, UK. Haemolysin testing was done by reacting freshly-prepared standard A, B, AB, and O red cell suspensions with sera from each participant. Sera which tested positive for haemolysin was further titrated, and the results read visually. Ethical approval was obtained from the Ministry of Health in Benin City. The prevalence of haemolysin among the 200 participants was 16% (32 out of 200). α haemolysin only was found in 14(7.0%), β haemolysin only in 11(5.5%), while 7(3.5%) donor samples were found to have both α and β haemolysin. Considering a significant p-value of ≤0.05, Statistical analysis (Chi-Square test) using IBM SPSS v22 showed no relationship between gender(p=0.66), age group(p=0.12), and rhesus D status (p=0.15) with the prevalence of haemolysin. Patients with a previous history of immunogenic stimuli such as vaccination, pregnancy, immunization, organ or tissue transplant are likely to develop haemolysins (p=0.036). 13% of all samples analyzed in this study had visual titres of 8 and above which is able to cause in-vivo haemolysis. The significance of transfusing group o blood with high titre haemolysin is a resulting haemolytic blood transfusion reaction. Therefore, the indiscriminate use of group O blood for non-group O recipients is discouraged, considering the haemolysin prevalence obtained in this study. In case of scarcity of blood and emergency, all blood group O donor units must be tested for the presence of haemolysin. Blood units found negative can be given to non-O patients while those that test positive are referred to as “Dangerous blood group O” and should be reserved for group O recipients only.