Alloimmunization to Rh Antigen (D, C, E, C, E) Among Pregnant Women Attending Antenatal Care in South Western Uganda.

Introduction: Maternal red cell alloimmunization to Rh antigen in pregnant women occurs when the immune system is sensitized by foreign red blood cell surface antigens, in this case fetal red blood cells, inducing an immune response. Various antigens of blood group systems may cause alloimmunization, especially the Rh, Kel, Fy, JK, and MNS systems. This study aimed to determine alloimmunization to the different frequencies of Rh antigen among pregnant women in South Western Uganda. Methods: A total of 1369 pregnant women consented and were recruited into a cross-sectional study during their regular antenatal visits during the period August 2020 to July 2021. Samples (4 mL) of anticoagulated and coagulated blood were obtained, and Rh blood grouping including Rh antigen and the indirect antiglobulin test (IAT) was carried out using the agglutination technology of the LISS ID-Card technique in the Ortho Biovue ID-Micro Typing System. Results: Out of 1369 participants recruited to the study, 78 (5.7%) were D-, 1291 were D+, and 134 (9.8%) had alloantibodies. Among those with alloantibodies, 115 (85.8%) were D+ and 19 (14.2%) D-. The percentage alloimmunization according to the Rh antigens was highest in e (9.72%), c (2.48%), C (2.34%) and E (0.94%) antigens. With the ABO system, alloimmunization was highest in blood group B (10.7%), followed by A (10.6%), O (9.2%) and then AB (7.1%). Alloimmunization was more prevalent in D- (24%) than in D+ participants (8.9%). Rhesus antigen e was the most prevalent antigen (99.8%), followed by c. The alloimmunization rate of 9.8% among these participants is high, and appears in both D+ and D- women. The other Rhesus antigens are seen to cause alloimmunization, with antigen e causing the highest prevalence. In conclusion, there is a need to identify antibodies and study the outcome for clinical significance, especially in D+ women, to facilitate proper pregnancy management.

ABO and Rh Antigen Distribution Among Pregnant Women in South Western Uganda.

Introduction: ABO and Rh are the major blood group systems in Transfusion Medicine, the ABO system based on two red cell antigens (A, B) while the Rh has about 50 antigens of which five are highly clinically significant (D, C, c, E, e). These vary among races and ethnic groups. Blood type phenotype incompatibility between mother and fetus may result in antigen mismatch, triggering alloimmunization, and thus causing hemolytic transfusion reaction (HTR), which results in hemolytic disease of fetus and newborn (HDFN). This study aimed to determine the frequencies of ABO and rhesus blood group antigen in the pregnant women in South Western Uganda. Methods: A cross-sectional study was carried out on 1369 pregnant women who were recruited and provided consent to participate during their regular antenatal visits between August 2020 and July 2021. Four milliliters (4mL) of EDTA-anti-coagulated blood samples were collected and ABO and Rh-blood grouping including Rh antigen screening was done using the agglutination technology comprised of glass beads and reagent contained in a column of the Ortho Biovue ID Micro Typing System (Ortho Clinical Diagnostics, New Jersey, USA). The Rh antigen phenotypes and frequencies were then determined. Results: There was percentage distribution of 99.8%, c 99.3%, D 94.3%, C 19.2% and E 15.9%, with Rh cDe/cDe (65.1%) being the most common phenotype followed by cDe/CDe (15%), cDe/cDE (10.8%) and cDE/cDE 0.1% least common. The ABO grouping frequency was obtained as O 49.4%, A 29.5%, B 17.0% and AB 4.1%, with D positivity at 94.3%. Discussion: Population genetic variations result in varied expressions of red cell antigens that may have clinical complications. Knowledge of the presence of these Rh antigen distributions and phenotype frequencies during pregnancy help in rational management of the pregnancy, alloimmunization and better approach to safe blood transfusion.

The utility of 'home-made' reagent red blood cells for antibody screening during pre-transfusion compatibility testing in Uganda.

BACKGROUND: The WHO recommends that pre-transfusion testing should include ABO/RhD grouping followed by screening for red blood cell (RBC) alloantibodies using the indirect antiglobulin test (IAT). However, in Uganda, current practice does not include RBC alloantibody screening. OBJECTIVE: To assess the utility of 'home-made' reagent RBCs in alloantibody screening. MATERIALS AND METHODS: In a laboratory-based study, group O RhD positive volunteer donors were recruited and their extended phenotype performed for C, c, E, e, K, Fya, Fyb Jkb, S and s antigens. These 'home-made' reagent RBCs were preserved using Alsever's solution and alloantibody detection tests performed. For quality assurance, repeat alloantibody screening of patients' samples was done at Bloodworks Northwest Laboratory in Seattle, United States. RESULTS: A total of 36 group O RhD positive individuals were recruited as reagent RBC donors (median age, 25 years; range, 21 - 58 years; male-to-female ratio, 1.6:1). Out of the 311 IATs performed, 32 (10.3%) were positive. Confirmatory IAT testing in the United States was in agreement with the findings in Uganda. CONCLUSION: Use of 'home-made' reagent RBCs during pre-transfusion testing in Uganda is feasible. We recommend the introduction of pre-transfusion IAT alloantibody screening in Uganda using 'home-made' reagent RBCs to improve transfusion safety.

Assessment of the quality of stored blood for transfusion at Mbarara Regional Referral Hospital, Southwestern Uganda.

Aim and objective: To assess the quality of blood stored for transfusion at Mbarara Regional Referral Hospital (MRRH) regarding bacterial contamination, malaria infection, and laboratory audit status. Materials and methods: Whole blood and packed red blood cells at MRRH were critically inspected for visual anomalies, and a portion of this blood was aseptically collected and analyzed for Plasmodium species and bacterial contamination using culture methods. For culture positive samples, drug susceptibility testing (DST) was done using the Kirby-Bauer disc diffusion method. An audit using Stepwise Laboratory quality Improvement Process Towards Accreditation (SLIPTA) quality checklist was conducted. The obtained data were analyzed as frequencies and proportions at 95% confidence interval (CI), and significance levels of relatedness were set at p-values<0.05. Results: Of the 202 samples analyzed, 6 (3%) had bacteria while 3 (1.5%) had Plasmodium falciparum trophozoites. The bacterial isolates were Staphylococcus aureus (N=4, 66.7%); Corynebacterium spp (N=1, 16.7%) and Micrococcus spp (N=1, 16.7%). Staphylococcus aureus showed sensitivity to chloramphenicol, oxacillin, amikacin, and gentamycin. Thirty (14.9%) of these units had visually detectable anomalies, and the laboratory audit score was 53.8%. Conclusion: The quality of some blood stored for transfusion at MRRH was inadequate, and the laboratory quality standard based on SLIPTA was low. Based on this, it is crucial to always insist on aseptic measures at all stages (phlebotomy, processing, transporting, and blood storage) and consider more assessment of the donor risk to minimize transfusion-transmitted malaria. It is plausible to standardize the hospital blood transfusion laboratory and revive hemovigilance by the hospital transfusion committee.

Assessment of the diagnostic performance of TrueHb® point-of-care hemometer compared with Sysmex i3 analyzer among patients at International Hospital Kampala, Uganda.

Aim/Objective: To assess the diagnostic performance of TrueHb® point-of-care (POC) hemometer compared with Sysmex i3 analyzer at International Hospital Kampala, Uganda. Materials and methods: We analyzed ethylenediaminetetraacetic acid blood samples to estimate hemoglobin (Hb) levels using parallel testing with TrueHb® hemometer and Sysmex i3 analyzer. Data were analyzed to ascertain the diagnostic performance of the test assays using the Bland and Altman method. Sensitivity, specificity, positive and negative predictive values were calculated. Results: The study enrolled 402 patients; of these, 156 (38.8%) were males. The average Hb levels were 8.7±1.8 and 13.3±2.6 g/dL for the anemic and nonanemic patients, respectively. One hundred and fifty-five participants were anemic, giving anemia prevalence of 38.56% (95% CI: 35.17-40.38). The mean difference of the TrueHb® and Sysmex i3 assays was 2.2219 (SD 1.07915), and the two devices did not show a difference in their measurements (t=-2.407, p-value 0.017, 95% CI: -0.095-0.010). Further, they showed a significant level of agreement (t=41.281; 95% CI: 2.1161-2.3277) and intraclass correlation coefficients (ICC=0.793). The sensitivity, specificity, positive and negative predictive values were 100.00%, 51.01%, 55.16% and 100.00%, respectively. The average performance turnaround time (TAT) for the TrueHb® hemometer was 2.46 mins (95% CI: 2.37-2.55). Conclusion: TrueHb® POC hemometer is an accurate POC for Hb estimation with a good performance agreement with the Sysmex i3 analyzer. This, coupled with its utility aspects, makes it a good diagnostic tool in a high anemia burden and low-resource setting.

Human T-Cell Lymphotropic Virus Types 1 and 2 Seropositivity among Blood Donors at Mbarara Regional Blood Bank, South Western Uganda.

Background. The human T-cell lymphotropic virus types 1 and 2 (HTLV 1/2) are retroviruses associated with different pathologies. HTLV-1 causes adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP); HTLV-2 is not clearly associated with a known clinical disease. Both viruses may be transmitted by whole blood transfusion, from mother to child predominantly through breastfeeding, and by sexual contact. Presently, none of the regional blood banks in Uganda perform routine pretransfusion screening for HTLV. The aim of this study was to determine the prevalence of anti-human T-cell lymphotropic virus types 1/2 (HTLV-1/2) antibodies among blood donors at Mbarara Regional Blood Bank in South Western Uganda. A cross-sectional study was conducted between June 2014 and September 2014. Methodology. Consecutive blood samples of 368 blood donors were screened for anti-HTLV-1/2 antibodies using an enzyme linked immunosorbent assay (ELISA). Samples reactive on a first HTLV-1/2 ELISA were further retested in duplicate using the same ELISA. Of the three hundred and sixty-eight blood donors (229 (62.2%) males and 139 (37.8%) females), only two male donors aged 20 and 21 years were HTLV-1/2 seropositive, representing a prevalence of 0.54%. Conclusion. HTLV-1/2 prevalence is low among blood donors at Mbarara Regional Blood Bank. Studies among other categories of people at risk for HTLV 1/2 infection should be carried out.

Red blood cell alloimmunization in transfused patients in sub-Saharan Africa: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: Previous studies of Sub-Saharan Africans show significant alloimmunization to red blood cell (RBC) antigens, but country-specific data are limited. Thus, the aim of this study was to estimate, by meta-analysis, the overall proportion of red blood cell alloantibodies among transfused patients. METHODS: We systematically searched Medline, Embase, and the Africa-Wide Information database to identify relevant studies in any language. Case reports, comments, letters, conference abstracts, editorials, and review articles were excluded. Of the 269 potentially relevant articles, 11 studies fulfilled our selection criteria. RESULTS: Overall proportions of alloimmunization were 6.7 (95% CI: 5.7, 7.8) per 100 transfused patients. With regard to antibody specificity, among clinically significant antibodies, anti-E ranked as the most common, followed by anti-K, anti-C and anti-D. CONCLUSION: Meta-analysis of available literature quantifies and qualifies the clinical challenge of RBC alloimmunization among transfused patients in Sub-Saharan Africa. These results should drive policy decisions in favour of routine testing of RBC antigens and irregular antibodies for transfused patients as a standard of care throughout Sub-Saharan Africa.

Occurrence of anti-D alloantibodies among pregnant women in Kasese District, Western Uganda.

OBJECTIVES: This study was undertaken to determine the distribution of ABO/RhD (rhesus D antigen) blood phenotypes, prevalence of anti-D alloantibodies, and the risk factors for alloimmunization among pregnant women in Kasese District, Western Uganda. MATERIALS AND METHODS: Ethylenediamine tetraacetic acid-containing plasma samples and serum samples were taken from pregnant women attending the antenatal clinic. The blood groups were identified using the microplate grouping method, while the presence of anti-D alloantibodies was detected by the indirect antiglobulin test (IAT). Data were also collected from the pregnant women on the risk factors associated with anti-D alloantibody formation. RESULTS: Among the 726 participants, the blood group distribution was as follows: O: 356 (49.%); A: 190 (26.%); B: 152 (21%); and AB: 28 (4%). A total of 28 (3.86%) pregnant women were RhD negative. Anti-D alloantibodies were detected in 88 (12.1%) of the participants; and of these, 13 (14.8%) were RhD negative. Statistically significant risk factors for anti-D alloimmunization included miscarriage, stillbirth, and postpartum hemorrhage. CONCLUSION: Blood group O was the most common among the pregnant women in this study and the prevalence of Rh negativity was 3.8%. The frequency of anti-D alloimmunization among pregnant women in Kasese District was 12.12%, with 85.5% of these being RhD positive. Risk factors such as a history of stillbirths, miscarriages, and incidence of postpartum hemorrhage were significantly associated with anti-D alloimmunization. There is a need to routinely carry out antenatal blood grouping and IAT screening on pregnant women in Uganda to detect anti-D alloimmunization. Given the high prevalence of anti-D alloantibody formation among RhD-positive women, we recommend additional research studies on the role of autoimmunity among antigen-positive women, as well as the occurrence of RhD variants plus their implications on hemolytic disease of the fetus and newborn, in Uganda.

Prevalence of HIV-related thrombocytopenia among clients at Mbarara Regional Referral Hospital, Mbarara, southwestern Uganda.

AIMS/OBJECTIVES: We aimed to determine the prevalence and correlates of thrombocytopenia among people living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) and to assess occurrence of antiplatelet antibodies, among thrombocytopenic HIV clients at Mbarara Regional Referral Hospital, southwestern Uganda. MATERIALS AND METHODS: This was a retrospective review of hematologic results at enrollment to HIV care from 2005 to 2013. The prevalence and correlates of thrombocytopenia were estimated based on the Immune Suppressed Syndrome (ISS) Clinic electronic database. A cross-sectional study determined the occurrence of antiplatelet antibodies, using the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) technique. RESULTS: We reviewed 15,030 client records. The median age was 35.0 (range 18-78; interquartile range [IQR] 28-42) years, and there were 63.2% (n=9,500) females. The overall prevalence of thrombocytopenia was 17.4% (95% confidence interval [CI]: 16.8%-18.0%). The prevalence of thrombocytopenia was 17.8% (95% CI: 17.1%-18.4%) among antiretroviral therapy (ART)-naïve clients (n=2,675) and was 13.0% (95% CI: 0.3%-21.9%) for clients who were on ART (n=6). The study found a significant association between thrombocytopenia and other cytopenias, CD4 counts, ART, and deteriorating HIV stage (P<0.05). Two of the 40 participants (5.0%) had antiplatelet antibodies. CONCLUSION: This study has showed a high prevalence of HIV-related thrombocytopenia. Antiplatelet antibodies were found in 5.0% of HIV-infected thrombocytopenic participants. Our study shows a significant association of thrombocytopenia burden in a high-HIV study population (Southwest Uganda); therefore, there is need to monitor platelet counts and initiate platelet transfusion in our blood banking practices, to avert possible risks of bleeding.

Transfusion Medicine in Sub-Saharan Africa: Conference Summary.

In November 2014, a 3-day conference devoted to transfusion medicine in sub-Saharan Africa was held in Kampala, Uganda. Faculty from academic institutions in Uganda provided a broad overview of issues pertinent to transfusion medicine in Africa. The conference consisted of lectures, demonstrations, and discussions followed by 5 small group workshops held at the Uganda Blood Transfusion Service Laboratories, the Ugandan Cancer Institute, and the Mulago National Referral Hospital. Highlighted topics included the challenges posed by increasing clinical demands for blood, the need for better patient identification at the time of transfusion, inadequate application of the antiglobulin reagent during pretransfusion testing, concern regarding proper recognition and evaluation of transfusion reactions, the expanded role for nurse leadership as a means to improve patient outcomes, and the need for an epidemiologic map of blood usage in Africa. Specialty areas of focus included the potential for broader application of transcranial Doppler and hydroxyurea therapy in sickle cell disease, African-specific guidelines for transfusion support of cancer patients, the challenges of transfusion support in trauma, and the importance of African-centered clinical research in pediatric and obstetric transfusion medicine. The course concluded by summarizing the benefits derived from an organized quality program that extended from the donor to the recipient. As an educational tool, the slide-audio presentation of the lectures will be made freely available at the International Society of Blood Transfusion Academy Web site: http://www.isbtweb.org/academy/.

Red blood cell alloimmunization from an African perspective.

PURPOSE OF REVIEW: Red blood cell (RBC) alloimmunization occurs when individuals are exposed to erythrocytes that express blood group antigens different from their own. Consequences of alloimmunization include hemolytic disease of the fetus and newborn and hemolytic transfusion reactions, with potentially serious morbidity and mortality. Patients who formed antibodies showed a four to five times increased risk for additional alloantibodies upon further transfusion exposure and may be at increased risk for transfusion reactions. In view of the main transfusion indications in Africans (e.g. malaria and pregnancy), the lifetime risk of exposure to multiple transfusion events is substantial, stressing the need for information on RBC alloimmunization in African transfusion recipients. RECENT FINDINGS: Three cross-sectional studies on RBC alloimmunization from two African countries of Uganda and Malawi showed that 1-6% of transfused patients possessed clinically relevant RBC antibodies. SUMMARY: Regarding RBC compatibility testing for transfusion, ABO/D typing is mandatory in African settings but complete crossmatches are not routinely performed. Despite the limited data on posttransfusion alloimmunization, a complete crossmatch for patients with past transfusions could be recommended. However, more information on blood group distribution in Africans and RBC alloimmunization rates and specificity is needed to consider immunoprophylaxis for hemolytic disease, pretransfusion testing, and preventive strategies to avoid transfusion-induced alloimmunization.

Red blood cell alloimmunization in sickle cell disease patients in Uganda.

BACKGROUND: Blood transfusion is an integral part in the management of sickle cell disease (SCD) patients. Alloimmunization is a recognized complication of red blood cell (RBC) transfusions with consequences including delayed hemolytic transfusion reactions and difficulties in getting compatible blood for future transfusions. The objective of this study was to determine the frequency of RBC alloimmunization in SCD patients in Uganda where pretransfusion screening for alloantibodies is not practiced. STUDY DESIGN AND METHODS: In a cross-sectional study, SCD patients at Mulago Hospital Sickle Cell Clinic, Kampala, Uganda, were investigated. The demographic characteristics and transfusion history were recorded. Blood samples were drawn from consenting, previously transfused patients and RBC alloimmunization was demonstrated using immunohematologic techniques. RESULTS: There were 428 patients (median age, 12 years; female/male ratio, 1.0) and they had received a median of 3 units in a median of three transfusion episodes. Twenty-six patients (6.1%) possessed RBC alloantibodies and 21 (80.7%) of them had received up to 10 transfusions. A total of 30 alloantibodies was found; 20 (66.7%) and 5 (16.6%) belonged to Rh and MNS blood groups, respectively. Five of the alloimmunized patients had multiple antibodies. CONCLUSIONS: The rate of RBC alloimmunization in Ugandan SCD patients was 6.1%. The homogeneity between donors and SCD patients plus the low transfusion load may explain this immunization frequency. Nevertheless, our study confirms the significance of RBC alloimmunization as a complication in Ugandan SCD patients. Therefore, there is need to improve immunohematologic testing in Uganda so that RBC alloimmunization and its consequences may be prevented.