Characteristics of ABO Antibodies in Group O Malaysian Blood Donors.

Background: Haemolytic transfusion reactions (HTRs) due to anti-A and anti-B antibodies in Group O blood products are rare but potentially fatal. This study aimed to identify the prevalence of high ABO antibody titre and the immunoglobulin (Ig) classes (IgM only or with IgG) and the prevalence of haemolysin antibodies in Group O blood donors. Methods: Plasma from Group O blood donors was tested by using antibody titration at room temperature. Titres ≥ 64 were considered high. The plasma was treated with 0.01 M dithiothreitol (DTT) to determine the presence of IgG antibodies and titre. IgG titres ≥ 64 were considered high. Tests for haemolysis were conducted by mixing the plasma with 3% fresh A1 and B cell suspensions and incubating at 37 °C. The haemolysis was observed macroscopically. Results: Of 311 donors, 238 (76.5%) showed high anti-A and/or anti-B antibody titres. The highest antibody titre obtained was 256. Female and younger donors (< 40 years old) had higher anti-A and anti-B titres. The anti-B titre showed an association with gender (P < 0.001), and was high in female donors (77.8%). Males aged over 50 years old were found to have low mean titre antibodies. Most donors had both IgM and IgG ABO antibodies. The prevalence of haemolysins in our population was 3.5%. Conclusion: Most of our O blood donors had a high ABO antibody titre but a low prevalence of haemolysins. Males aged over 50 years old are the best O donors for preventing HTRs, particularly when mismatch transfusion is required. We recommend a transfusion unit screen for ABO antibody titre in younger female donors (< 40 years old), to prevent the transfusion of high titre O blood products into non-O recipients.

Challenges in the Diagnosis of Beta-thalassemia Syndrome: The Importance of Molecular Diagnosis.

Patients with heterozygous ß-thalassemia are generally asymptomatic. However, the intermediate phenotype is uncommon, and patients require further investigation to confirm the diagnosis. We describe a 32-year-old woman (gravida 3, para 2) with heterozygous ß-thalassemia who presented with symptomatic anemia and had a history of frequent blood transfusion in each pregnancy. Physical examination was unremarkable. Laboratory results at presentation showed hypochromic microcytic anemia with reticulocytosis. Molecular study revealed intermedia phenotypes resulting from coinheritance of heterozygous ß-globin chain mutation (IVS1-5) and a rare heterozygous α-globin triplication (αααanti-3.7). In this case report, we discuss the laboratory diagnostic approaches and the challenges faced in investigating this case.

Para-Bombay Phenotype of a Pregnant Mother in Malaysia: Transfusion for an Extremely Premature Baby.

Para-Bombay blood phenotype is a rare blood group with limited cases reported worldwide. This blood group is characterized by the absence of ABH antigen on red blood cells but presence of ABH secretor substances in the body secretion. This rare phenotype is usually misinterpreted as O and may endanger the patient if urgent blood transfusion is required. A mother who was labelled as group O Rh D positive during antenatal follow-up was found to have ABO discrepancy during delivery. The newborn was admitted for extremely premature delivery at 25 weeks. As the baby required transfusion, problem arose during cross matching with the mother's sample. It was found that the mother was group O Rh D positive in forward grouping. However, the reverse grouping showed the presence of reaction (2+) in O cells. The baby was grouped as O Rh D positive. As transfusion was urgently needed due to baby's unstable condition, group O Rh D positive packed cell was found compatible with baby's serum, subsequently transfused. Bombay blood donor was contacted, and the donated blood was sent to the hospital for further management. Further investigations were performed, indicating that the mother is para-Bombay A. Due to recent transfusion to baby, we suggested to repeat baby's blood group after the baby is one year old. Para-Bombay was usually mislabelled as O if the sample was not tested with O cell in reverse grouping. Additional tests may be needed during antenatal follow-up to prevent complications during delivery, which requires emergency blood transfusion.

A case of naturally occurring anti-Dia antibody in a young man.

The Diego (Di) blood group system comprises 22 antigens located on the band 3 protein, most of which are low-prevalence antigens. The majority of antibodies to Diego system antigens were of clinically insignificant; however anti-Dia, -Dib, -Wra, -ELO and-DISK may cause hemolytic disease of the fetus and newborn (HDFN) and transfusion reaction. We reported a case of naturally occurring of anti-Dia in a young man who presented to our hospital for wound debridement of fingers injury. His serological results were suggestive of anti-Dia antibody, and his molecular blood group showed he has Di (a-b+) antigen. Anti-Dia may be clinically significant. It can cause mild-to-severe HDFN, but there are only infrequent reports of it being clearly implicated in a hemolytic transfusion reaction. We suggest the need for reagent red blood cell panels to include Dia antigen-positive cells in antibody identification tests for our populations.

Prevalence of Near-miss Events of Transfusion Practice and Its Associated Factors amongst House Officers in a Teaching Hospital.

OBJECTIVES: A near miss in transfusion practice is defined as a deviation from standard procedures discovered before transfusion and can lead to a transfusion error. Information on near-miss events provides pivotal data on areas of improvement to prevent actual errors in the future. Our study sought to determine the prevalence and rate of near-miss events and their associated factors amongst house officers (HO) in Hospital Universiti Sains Malaysia. METHODS: The initial part of this study is a descriptive cross-sectional study involving data collection from all requests sent for group, screen, and hold (GSH) and group and cross match (GXM) tests from 2011 to 2017. The association between sociodemographic, workplace, and experience factors with near-miss events amongst HO was analyzed with a case-control study using logistic regression. RESULTS: We reported 83 near-miss events with a prevalence of 0.034% (95% confidence interval 0.027-0.042). The rate of near-miss events was one in every 2916 requests. The mean reporting rate was 11.9 events per year. Clinical near miss predominated at 89.2% compared to 10.8% laboratory near miss. Mislabeled events (33.7%) were more than miscollected events (10.8%). HO were implicated with most events (83.1%). Most events were predominantly in the medical and obstetrics and gynecology wards amounting to 31.3% each. We found a significant association between the ages of HO with near-miss events. CONCLUSIONS: The prevalence of near-miss events in our hospital was relatively low. Our study has shown areas for improvement include improving sampling practices in clinical areas, adequate training of laboratory technicians, and providing proper transfusion education. Interventions such as encouraging compliance to guidelines and training in clinical and laboratory areas to minimize the risk of mistransfusion should be considered.

Hemolytic Disease of Fetus and Newborn in a Primigravida with Multiple Alloantibodies Involving Anti-Jka and Anti-E: A Case Report.

The majority of hemolytic disease of the fetus and newborn (HDFN) reported in the literature is due to ABO and rhesus incompatibility. However, there are also other minor blood groups that have been identified as a cause of HDFN, although the occurrence is much rarer. The antibody screening program for D negative mother and the anti-D immunoglobulin treatment showed a significant reduction of the occurrence of HDFN secondary to anti-D. In a developed country, the screening for red blood cell antibody in the pregnant mother other than anti-D reduced the possibility of HDFN occurrence hence reduced the fetal morbidity and subsequently increased the fetal well being during pregnancy and after the postnatal period. In this case report, we discuss HDFN in a primigravida patient secondary to multiple alloantibodies (anti-Jka and anti-E). The baby developed jaundice with bilirubin levels approaching the exchange transfusion level. However, with extensive phototherapy and immunoglobulin treatment, the child did not require exchange transfusion. We also included the importance of the routine antenatal antibody screening program. This practice will help the transfusion center to find the antigen negative blood in a timely manner and reduce the morbidities and mortalities of HDFN among the newborns.

Prevalence of Red Blood Cell Alloimmunization among Transfused Chronic Kidney Disease Patients in Hospital Universiti Sains Malaysia.

OBJECTIVES: Red blood cell (RBC) immunization is a common complication in blood transfusion recipients. Patients with chronic kidney disease (CKD) eventually develop anemia, which is multifactorial, and requires regular blood transfusions, which exposes patients to the development of RBC antibodies. We sought to determine the prevalence and specificity patterns of RBC immunization and its risk factors among transfused CKD patients. METHODS: We conducted a cross-sectional study over one year from January to December 2018 in the Transfusion Medicine Unit, Hospital Universiti Sains Malaysia. A total of 249 samples were recruited from CKD patients who received a blood transfusion (at least one-pint), which only match for ABO and Rh(D) antigen. The serum was screened for the presence of the RBC antibody using the gel agglutination technique (Diamed gel cards). Samples with positive antibody screening were subjected to antibody identification. RESULTS: Of the 249 transfused CKD patients, 31 (12.4%) developed RBC immunization. Thirty (12%) were alloimmunized, and one (0.4%) was autoimmunized. Anti-Mia was the most common antibody (n = 14, 46.7%) among alloantibodies, followed by anti-E (n = 7, 23.3%). There was a significant association between pregnancy history with the development of antibodies whereas, no significant association was found between sociodemographic background, stage of CKD, hemodialysis status, underlying medical illness, and number of packed cell transfusions with the development of RBC antibodies. CONCLUSIONS: One-eighth of our patient cohort had RBC alloimmunization, and the risk was increased in patients with a history of pregnancy. We propose Rhesus RBC phenotyping and to supply blood match Rhesus antigen in CKD patients, especially patients of reproductive age.

Autologous Peripheral Blood Stem Cell Transplantation Among Lymphoproliferative Disease Patients: Factors Influencing Engraftment.

OBJECTIVES: Autologous peripheral blood stem cells transplantation (APBSCT) is a therapeutic option which can be used in various hematological, neoplastic disorders including lymphoproliferative disease (LPD). Differences in patient populations and treatment modalities in different transplant centers mean it is important to improve the knowledge of the different factors affecting engraftment after APBSCT for the success of this procedure. We sought to determine the factors influencing neutrophil and platelet engraftment after APBSCT in patients with LPD. METHODS: We conducted a retrospective review of 70 patients with LPD (35 with lymphoma and 35 with multiple myeloma) who had undergone APBSCT between January 2008 and December 2016. Data obtained included disease type, treatment, and stem cell characteristics. Kaplan-Meier analysis was performed for probabilities of neutrophil and platelet engraftment occurred and was compared by the log-rank test. The multivariate Cox proportional hazards regression model was used for the analysis of potential independent factors influencing engraftment. A p-value < 0.050 was considered statistically significant. RESULTS: Most patients were ethnic Malay, the median age at transplantation was 49.5 years. Neutrophil and platelet engraftment occurred in a median time of 18 (range 4-65) and 17 (range 6-66) days, respectively. The majority of patients showed engraftment with 65 (92.9%) and 63 (90.0%) showing neutrophil and platelet engraftment, respectively. We observed significant differences between neutrophil engraftment and patient's weight (< 60/≥ 60 kg), stage of disease at diagnosis, number of previous chemotherapy cycles (< 8/≥ 8), and pre-transplant radiotherapy. While for platelet engraftment, we found significant differences with gender, patient's weight (< 60/≥ 60 kg), pre-transplant radiotherapy, and CD34+ dosage (< 5.0/≥ 5.0 × 106/kg and < 7.0/≥ 7.0 × 106/kg). The stage of disease at diagnosis (p = 0.012) and pre-transplant radiotherapy (p = 0.025) were found to be independent factors for neutrophil engraftment whereas patient's weight (< 60/≥ 60 kg, p = 0.017), age at transplantation (< 50/≥ 50 years, p = 0.038), and CD34+ dosage (< 7.0/≥ 7.0 × 106/kg, p = 0.002) were found to be independent factors for platelet engraftment. CONCLUSIONS: Patients with LPD who presented at an early stage and with no history of radiotherapy had faster neutrophil engraftment after APBSCT, while a younger age at transplantation with a higher dose of CD34+ cells may predict faster platelet engraftment. However, additional studies are necessary for better understanding of engraftment kinetics to improve the success of APBSCT.