Assessment Of Phenotypic Properties Of The Rhesus And Kell Blood Group Systems Among Blood Donors And Pregnant Women In Namibia

ABSTRACT

Introduction

A determination of the phenotypic frequencies of blood group systems C, c, E, e and Kell among the Namibian blood donors and pregnant women and the prevalence of these antigens in Namibia was carried out. Two thousand nine hundred and eight six blood donor specimens and four hundred and eighty-four specimens from pregnant women were randomly selected for antigen characterisation. Donated specimens that were processed for grouping and Transfusion Transmissible Infections (TTIs) by NaMBTS and ready for discard were collected by the researcher for testing.

The main aim was to determine the prevalence of C, c, E, e and Kell antigens among the Namibia blood donors and pregnant women and advice NaMBTS and the Ministry of Health and Social Services (MoHSS) on the findings in order to improve the outcome of patients who will be receiving donated blood and the pregnant women. This was to lay the foundation for further studies to establish a database for typed donors in Namibia and then store blood that is antigen negative and reduce the risks of Haemolytic Disease of the Foetus and the New-born (HDFN) and Haemolytic Transfusion Reaction (HTR). In some cases, the survival of the red blood cells that will have been transfused is shortened by the effect of transfused antigens. This is the first time this research has been carried out in Namibia.

Methods

Reagents were supplied by Rapid labs (Ltd) 2016, Essex, United Kingdom and testing procedures were carried out according to the manufacturer’s Instructions. Anti –E, Anti-e, Anti- Kell, Anti- C and Anti –c reagents were used to determine the corresponding human red cell antigens. Monoclonal human IgM antibodies were used for blood grouping using the agglutination test procedure. If red cells with a specific antigen were mixed with the corresponding reagent, agglutination was expected. If agglutination took place it meant that the test was positive for that particular antigen. If agglutination didn't take place it showed the absence of that particular antigen and the test was regarded as negative.

Results

The results that were obtained showed that all the specimens that were tested had an average prevalence level of 6.6 % for C, c, E, e and Kell antigens and the one that was a bit high (10.5%) was the e-antigen for both the donors and the Ante Natal Clinic patients (ANC) with 10.4% and 10.5% respectively. The K antigen had a prevalence of 8.7% on donors and 7.2 % on ante-natal patients. C-antigen had a prevalence of 6.0% on donors and 7.0% on ANC patients. E antigen had the same prevalence in both donors and ANC patients with 2.1 %. The Namibian Donor population compares well with other countries in the world.

Conclusion

The conclusion that can be derived from the results obtained is that the prevalence of e-antigens in the Namibia population is high and this is one of the antigens that is generally implicated in immunisation during pregnancy and blood transfusion reactions hence the need to add it on routine screening for antibodies. There is a need to screen antigens such as ein both donor specimens and antenatal patients and to have further research to see if there is a need to actually have banks with a specific database for typed donors.