An investigation of the protective effect of alpha+-thalassaemia against severe Plasmodium falciparum amongst children in Kumasi, Ghana

Background: The alpha+-thalassaemias are the most common monogenic disorders of humans, characterised by microcytic and hypochromic anaemia. Their high frequency reflects selective advantage against death from Plasmodium falciparum malaria. The most common type of alpha+- thalassaemia amongst people of African descent is the -α3.7 deletional type and affects 26-33% of Ghanaians. Plasmodium falciparum malaria is a major cause of mortality amongst children in sub-Saharan Africa. Unlike HbAS, HbAC and G6PD deficiency there remains debate about whether alpha+- thalassaemia protects against malaria and the mechanism for the protection. Methods: 1672 children of ≤10 years were recruited and individuals with G6PD deficiency, HbAC and Hb AS reported to protect against malaria were excluded. 732 children with Plasmodium falciparum were tested for Hb, RBC, MCV, MCH and parasite density. The subjects were then categorised into normocytic and microcytic using a cut off MCV value of 76fL and normochromic and hypochromic using a cut off MCH value of 25 pg. Microcytic hypochromic individuals were genotyped by Polymerase Chain Reaction for the -α3.7 deletional thalassaemia mutation. Results: The frequency of Plasmodium falciparum malaria in the studied population was 54.1%. There was a frequency of 21.0% for the heterozygous (-α/αα) and 8.3% for the homozygous (-α/-α) alpha+-thalassaemia, resulting in a carriage rate (α/αα & -α/-α) of 29.3%. Among the microcytic patients, geometric mean parasite density (GMPD) values were lower in the presence of an alpha+- thalassaemia genotype (-α/αα GMPD 9015, n=126 and -α/-α GMPD 6852, n=49) compared to normal genotype (αα/αα GMPD 51794, n=358) (p<0.001). Severe malaria (GMPD ≥100000/μL) was less prevalent in microcytic patients with an alpha+-thalassaemia genotype (-α/αα 11.9% and -α/-α 16.3%) than either normocytic patients or microcytic patients with a normal genotype (32.9% and 53.6% respectively) (p<0.03). GMPD values were lower in hypochromic alpha+-thalassaemia genotypes (-α/αα GMPD 1728, n=44 and -α/-α GMPD 7160, n=23) compared to normal genotype (αα/αα GMPD 48997, n=141) (p 5 g/dL had lower GMPD compared to the severely anaemic (Hb ≤ 5 g/dL) (p<0.001). The differences in severe Plasmodium falciparum parasitaemia as well as the GMPD between children ≤ 60 and > 60 months for both the homozygous and heterozygous alpha+-thalassaemia were not significant at p=0.399 and p=0.207 respectively. Conclusion: The severity of Plasmodium falciparum parasitaemia measured, as either GMPD or prevalence of severe parasitaemia was significantly lower in both the -α/αα and -α/-α- groups compared to microcytic individuals with normal genotype. Even though GMPD differed significantly amongst all alpha+-thalassemia genotypes, it was not driven by hypochromasia. Among the homozygous and heterozygous alpha+-thalassaemias, children with severe anaemia had a significantly high GMPD than their counterparts who were not severely anaemic making them more susceptible to severe malaria anaemia. No loss of protection was seen in children younger or older than 60 months and therefore the protective effect from severe malaria might not wane with age. The mechanism of protection from severe Plasmodium falciparum malaria is not clear, however the influence of microcytosis and hypochromasia on parasite density requires more research

Changes in potassium and sodium concentrations in stored blood

Potassium is the principal intracellular cation with sodium being the principal extracellular cation. Maintenance of the distribution of potassium and sodium between the intracellular and the extracellular compartments relies on several homeostatic mechanisms. This study analysed the effect of blood storage on the concentrations of potassium and sodium in stored blood and also determine any variations that may exist in their concentrations. 50mls of blood was sampled each from 28 units of evenly mixed donated blood in citrate phosphate dextrose adenine (CPDA-1)bags immediately after donation into satellite bag and stored at 4oC. Potassium and sodium concentration determinations were done on each ofthe 28 samples on day 0 (before blood was initially stored in the fridge), day 5, day 10, day 15 and day 20 of storage using the Roche 9180 ISEElectrolyte Analyser (Hoffmann-La Roche Ltd, Switzerland). data analysis showed significant changes in the potassium and sodium concentrationswith a continuous rise in potassium and a continuous fall in sodium. A daily change of 0.59mmol/l and 0.50mmol/l was observed in the potassiumand sodium concentrations respectively. We showed steady but increased daily concentrations of potassium and decrease concentrations ofsodium in blood stored over time at 4oC

Detection of Weak D (Du) Phenotype among Rh-D Negative Males and Females in Kumasi, Ghana

Weak Rh D phenotypes are very frequent in Africans. They are capable of causing alloimmunization in Rh D-negative individuals. Some weak Ds may elude routine typing using direct agglutination techniques. This study aimed at determining the prevalence of weak D phenotype among Rhnegatives, using indirect antiglobulin technique. A total of 400 donors between the ages of 16 and 35 years who were grouped by the blood bank were randomly sampled over a period of 2 months. Three hundred and sixty nine (92.25%) were typed as Rh D-positive and 31 (7.75%) RhD-negative. Two (6.45%) of the Rh D-negative donors were weak D positive while 29 (93.55%) were weak D negative. Among the males 25 (9.43%) were Rh D-negative and 240 (90.57%) RhD-positive. Two (8%) of the 25 males were weak D positive. Among the females, 6 (4.44%) were Rh D-negative and 129 (95.56%) RhD- positive. This implies that, there are people in Kumasi with weak D phenotype which cannot be detected by the direct monoclonal anti-D agglutination. Consequently, indirect antiglobulin test may be indicated for such individuals typed Rh D-negative. This study has shown the need for a comprehensive policy on appropriate testing of donors and newborns, and management of Rh D-negative mothers in the Region. This should include weak D testing of all Rh Dnegative blood donors before transfusion in Rh D-negative patient. Keywords: Rhesus D, weak Rh D, indirect antiglobulin test, Kumasi-Ghana Journal of Science & Technology (Ghana) Vol. 28 (3) 2008: pp. 34-4

An External Quality Assessment Of Haematology Laboratories-A Ghanaian Experience

Developed countries have guaranteed the quality of clinical laboratories through quality assurance programmes. However, these programmes have not received the needed attention in Ghanaian haematology laboratories, as is the case in many developing countries where visual counting of blood cells are the usual procedures. To assess the level of analytical quality of haematology laboratories in the Ashanti region of Ghana, form of an external quality assessment scheme was undertaken. The survey covered twelve haematology laboratories in both the public and the private sectors. Control blood samples were sent to the laboratories to be analyzed. The study, which lasted for five months, covered such routine haematological parameters as Hb, PCV, Total WBC and platelets. The results from these laboratories were compared to that of an automated cell counter using the Cell-Dyn 3700 (Abbot Diagnostic Division, USA). About 80% of the laboratories studied which were using the manual counting, achieved the medically accepted analytical performance for all the parameters except platelets, where the percentage of the laboratories dropped to about 70%. The study has established the need for a continuous internal and external quality assessment in haematology. Such practice together with continuous education of laboratory personnel and the provision of automated instruments will help to achieve optimum laboratory quality needed for proper health care delivery in the country. Keywords: External quality assessment, haematology laboratories, Ghana. Journal of Science and Technology Vol. 28 (1) 2008 pp. 17-2

The expression of SLAMF7 levels in malignant B cells: a novel therapeutic pathway for patients with CLL

Signalling lymphocyte activation molecule (SLAM) F7 is found on the surface of some immune cells including B-lymphocytes. Its activation leads to the proliferation or differentiation of immune cells. The objectives of the study were to measure SLAMF7 expression levels on B-CLL cells, and to upregulate the expression of SLAMF7 with phorbol myristate acetate (PMA) and Bryostatin. The levels of expression of SLAMF7 receptors of B-CLL cells from patients were measured; using immunofluorescence, flow cytometry, confocal microscopy and reverse transcriptase polymerase chain reaction (RT-PCR). The effects of treatments with PMA and Bryostatin were determined from different patients. Different levels of SLAMF7 expression were found to be associated with B-CLL cells from different patients. PMA treatment of B-CLL cells showed more positive SLAMF7 staining with the majority of the extracted B-CLL cell cases, while less positive results were associated with Bryostatin treatment. The study has shown that both PMA and Bryostatin could upregulate SLAMF7. Successful modulation of SLAMF7 expression may provide a novel target for the treatment of patients with CLL.Keywords: SLAMF7, RT PCR, Elotuzumab, Bryostatin, PM

Bacterial contamination of donor blood at the Tamale Teaching Hospital, Ghana

Background: Transfusion of bacterially contaminated blood can result in sepsis and will constitute a substantial health burden to the patient. Objective: To assess the level of transfusion related sepsis and the bacterial types responsible for the contamination at the Tamale Teaching Hospital in Ghana. Method: We sampled 80 refrigerated donor blood at the blood bank and cultured them for bacteria. The antimicrobial sensitivities of the isolates were also determined. Results: 14 blood bags representing 17.5% grew isolates of various bacteria. Ten (10) of the 14 isolates were Gram positive cocci representing 71.42% making it the commonest contaminant. 50% of the gram positive cocci were identified to be coagulase negative staphylococci and 21.42% were Staphylococcus aureus . There were 14.28% isolates which were Gram positive rods, and were identified to be Corynebacterium diphtheroids . There were two isolates which were Gram negative rods; one was identified as Escherichia coli and the other one Klebsiella pneumoniae . Sensitivity among the organisms were varied; as all the 14 (100%) of the organisms isolated were sensitive to amikacin, only 14.28% of the coagulase negative staphylococci were sensitive to co-trimoxazole, 28.5% were sensitive to ampicillin, 42.8% were sensitive to cefuroxime and 71.4% were sensitive to ciprofloxacin. Sensitivity to gentamicin was observed to be 85.7% and 28.5% were sensitive to Tetracycline. Only the 10 Gram positive cocci were tested against erythromycin and Cloxacillin; where 70.00% were sensitive to cloxacillin and 90% were sensitive to erythromycin. Conclusion: All the Staphylococcus aureus isolated were resistant to both ampicillin and cotrimoxazole. Potential dangers and consequences of transfusing multidrug resistance bacteria have been discussed

Use of whole blood as the routine transfusion product in Africa

In many countries in sub-Saharan Africa (sSA) whole blood is more commonly available from blood transfusion services than red cell concentrates. Although in recent years many countries have made significant progress in the implementing component preparation, this has largely been facilitated by external funding support. None of the sSA countries are leucocyte-reducing or irradiating blood for transfusion. Systems for the routine detection of adverse consequences of blood transfusions (hemovigilance) only exist where transfusion safety has been identified as a health priority by the government. As a resource the availability of blood transfusion in these countries is limited since less than 5 units of blood were donated per 1000 population far below the recommended requirement of 20 units/1000 per year. Young children are the main users of blood for transfusion in these sSA regions, largely due severe anaemia secondary to infection and sickle cell anaemia. Outcomes for children with severe anaemia are poor, even in those receiving a transfusion. Although it has been speculated that this may be due to transfusion-related cardiac or pulmonary events available data from observational studies and clinical trials indicates that these are rare complications of transfusion. Evidence from clinical physiology studies including those examining myocardial function before and after the receipt of whole blood provide reassuring evidence that volume overload is rare and clinical trials reporting outcomes in children receiving whole blood transfusion, including a Phase II trial examining higher volumes, indicate that there is no evidence of cardiac or pulmonary overload events