Evaluation of quantitative point-of-care test for measurement of glucose-6-phosphate dehydrogenase enzyme activity in Malaysia

INTRODUCTION

The treatment of Plasmodium vivax malaria with 8-aminoquinolines is contraindicated in glucose-6-phosphate dehydrogenase (G6PD) deficient individuals due to the risk of acute haemolytic anaemia. Effective G6PD screening is paramount to avoid adverse drug reactions. This study aimed to evaluate the performance of novel quantitative point-of-care (POC) tests as a new screening method for G6PD deficiency in Malaysia.

MATERIALS AND METHODS

A total of 153 neonatal cord blood, 99 peripheral blood of older children aged between 1 month to 12-years old, and 62 peripheral adult blood were screened for G6PD deficiency using two quantitative POC tests, CareStartTM biosensor (Carestart) and CareStartTM Biosensor 1 (S1). The results were compared with OSMMR2000D kit as a reference assay. Two statistical analyses were performed in this study to evaluate the POC test performances, the Spearman's correlation test and the Cohen's kappa method.

RESULTS

Both Carestart and S1 tests showed significant positive correlations to OSMMRS000D with r² = 0.7916 and r² = 0.7467. Their measurement of agreement showed a kappa (κ) value of 0.805 (p<0.001, 95% CI), and 0.795 (p<0.001, 95% CI), respectively. Analysis of the area under the Receiver Operating Curve (ROC) at 60% cut-off illustrated that the Carestart had 90.2% sensitivity, 98.9% specificity, 98.3% positive predictive value (PPV), and 93.8% negative predictive value (NPV). The corresponding values for the S1 were 95.2%, 100%, 100%, and 96.8%, respectively.

CONCLUSION

This study showed that the Carestart and S1 biosensors have high-performance reliability for screening of G6PD deficiency, which can guide safe prescriptions of anti-malaria medications and hence, eradication of Plasmodium vivax malaria.

Global Globin Network Consensus Paper: Classification and Stratified Roadmaps for Improved Thalassaemia Care and Prevention in 32 Countries

The Global Globin Network (GGN) is a project-wide initiative of the Human Variome/Global Variome Project (HVP) focusing on haemoglobinopathies to build the capacity for genomic diagnosis, clinical services, and research in low- and middle-income countries. At present, there is no framework to evaluate the improvement of care, treatment, and prevention of thalassaemia and other haemoglobinopathies globally, despite thalassaemia being one of the most common monogenic diseases worldwide. Here, we propose a universally applicable system for evaluating and grouping countries based on qualitative indicators according to the quality of care, treatment, and prevention of haemoglobinopathies. We also apply this system to GGN countries as proof of principle. To this end, qualitative indicators were extracted from the IthaMaps database of the ITHANET portal, which allowed four groups of countries (A, B, C, and D) to be defined based on major qualitative indicators, supported by minor qualitative indicators for countries with limited resource settings and by the overall haemoglobinopathy carrier frequency for the target countries of immigration. The proposed rubrics and accumulative scores will help analyse the performance and improvement of care, treatment, and prevention of haemoglobinopathies in the GGN and beyond. Our proposed criteria complement future data collection from GGN countries to help monitor the quality of services for haemoglobinopathies, provide ongoing estimates for services and epidemiology in GGN countries, and note the contribution of the GGN to a local and global reduction of disease burden.

Siriraj I Gγ(Aγδβ)0-thalassaemia causing severe thalassaemia intermedia in compound heterozygous state with IVS1-1(G→T) mutation

The Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia is a novel mutation involving a 118kb deletion of the β-globin gene cluster. It was first reported in 2012 in two unrelated families from the southern part of Thailand. The carriers in the heterozygous state are clinically asymptomatic. Nonetheless, its complex interaction with other β-thalassaemia could give rise to different clinical phenotypes, ranging from mild thalassaemia intermedia to thalassaemia major. We report here a case of a six-year-old Malay boy, presented with pallor, growth failure and hepatosplenomegaly. His haemoglobin at presentation was 9.2g/dL with a mean cell haemoglobin of 22.6pg and a mean cell volume of 69.9fl. His peripheral blood smear showed features of thalassaemia intermedia. Haemoglobin (Hb) analysis revealed markedly raised Hb F (83%), normal HbA2 levels and absent HbA. Deoxyribonucleic acid (DNA) analysis showed compound heterozygous IVS1-1 (G→T) β-globin gene mutation and Siriraj I ^Gγ(^Aγδβ)⁰-deletion (genotype β^IVS1-1/ β ^{Siriraj I deletion}). Both his father and elder sister are carriers of Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia while his mother carries IVS1-1 (G→T) gene mutation. Clinically, the patient is transfusion dependent on six weekly regime. To the best of our knowledge, this is the first reported case in Malaysia involving unique Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia and IVS1-1 (G→T) in a compound heterozygous state. In summary, detection of Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia is essential as this deletion can lead to severe disease upon interaction with a β-thalassemia point mutation as demonstrated in our case. The establishment of effective carrier screening and genetic counselling is important to prevent its adverse consequences.

H396P mutation in chronic myeloid leukaemia patient on nilotinib - A case report

INTRODUCTION

The advent of BCR-ABL1-targeted therapy with the tyrosine kinase inhibitor (TKI), for example, imatinib and nilotinib, marked a turning point in the therapy of chronic myeloid leukaemia (CML). However, a substantial proportion of patients experience primary or secondary disease resistance to TKI. There are multifactorial causes contributing to the treatment failure of which BCR-ABL1 kinase domain mutation being the most common. Here, we describe a case of a CML patient with H396P mutation following treatment with nilotinib.

CASE

A 60-year-old woman presented with abdominal discomfort and hyperleukocytosis. She was diagnosed as CML in the chronic phase with positive BCR-ABL1 transcripts. Due to the failure to obtain an optimal response with imatinib treatment, it was switched to nilotinib. She responded well to nilotinib initially and achieved complete haematological and cytogenetic responses, with undetectable BCR-ABL1 transcripts. However, in 4 years she developed molecular relapse. Mutation analysis which was done 70 months after commencement of nilotinib showed the presence of BCRABL1 kinase domain mutation with nucleotide substitution at position 1187 from Histidine(H) to Proline(P) (H396P). Currently, she is on nilotinib 400mg twice daily. Her latest molecular analysis showed the presence of residual BCR-ABL1 transcripts at 0.22%.

DISCUSSION/CONCLUSION

This case illustrates the importance of BCR-ABL1 mutation analysis in CML patients with persistent BCR-ABL1 positivity in spite of treatment. Early detection and identification of the type of BCRABL1 mutation are important to guide appropriate treatment options as different mutation will have different sensitivity to TKI.

Genetic Modifiers of Fetal Haemoglobin (HbF) and Phenotypic Severity in β-Thalassemia Patients

BACKGROUND

The phenotypic severity of β-thalassemia is highly modulated by three genetic modifiers: β-globin (HBB) mutations, co-inheritance of α-thalassemia and polymorphisms in the genes associated with fetal haemoglobin (HbF) production. This study was aimed to evaluate the effect of HbF related polymorphisms mainly in the HBB cluster, BCL11A (B-cell CLL/lymphoma 11A) and HBS1L-MYB (HBS1-like translational GTPase-MYB protooncogene, transcription factor) with regards to clinical severity.

METHODS

A total of 149 patients were included in the study. HBA and HBB mutations were characterised using multiplex PCR, Sanger sequencing and multiplex ligationdependent probe amplification. In addition, 35 HbF polymorphisms were genotyped using mass spectrometry and PCR-restriction fragment length polymorphism (PCRRFLP). The genotype-phenotype association was analysed using SPSS version 22.

RESULTS

Twenty-one HBB mutations were identified in the study population. Patients with HBB mutations had heterogeneous phenotypic severity due to the presence of other secondary modifiers. Co-inheritance of α-thalassemia (n = 12) alleviated disease severity of β-thalassemia. In addition, three polymorphisms (HBS1LMYB, rs4895441 [P = 0.008, odds ratio (OR) = 0.38 (0.18, 0.78)], rs9376092 [P = 0.030, OR = 0.36 (0.14, 0.90)]; and olfactory receptor [OR51B2] rs6578605 [P = 0.018, OR = 0.52 (0.31, 0.89)]) were associated with phenotypic severity. Secondary analysis of the association between single-nucleotide polymorphisms with HbF levels revealed three nominally significant SNPs: rs6934903, rs9376095 and rs9494149 in HBS1L-MYB.

CONCLUSION

This study revealed 3 types of HbF polymorphisms that play an important role in ameliorating disease severity of β-thalassemia patients which may be useful as a predictive marker in clinical management.

A Unique Interaction of IVS-I-1 (G>A) (HBA2: c.95+1G>A) with Hb Adana (HBA2: c.179G>A) Presenting as Transfusion-Dependent α-Thalassemia

Nondeletional α-globin mutations are known to cause more serious clinical effects than deletional ones. A rare IVS-I-1 (G>A) (HBA2: c.95+1G>A) donor splice site mutation interferes with normal splicing of pre mRNA and results in activation of a cryptic splice site as well as a frameshift mutation. Hb Adana [HBA2: c.179G>A (or HBA1)] is a highly unstable variant hemoglobin (Hb) resulting from a mutation at codon 59 on the HBA2 or HBA1 gene, recognized to cause severe α-thalassemia (α-thal) syndromes. We report a unique case of compound heterozygosity for these two mutations in a 9-year-old boy who presented with a Hb level of 5.3 g/dL and hepatomegaly at the age of 15 months. He required regular blood transfusions in view of a Hb level of <7.0 g/dL and failure to thrive. He had thalassemic red cell indices and peripheral blood film. The Hb electrophoresis only showed a raised Hb F level (3.3%) and a pre run peak but the Hb H inclusion test was negative. His father had thalassemic red cell indices but a normal Hb level. His mother had almost normal Hb levels and red cell indices. Hb Adana involving the HBA2 gene was detected by mutiplex amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in the proband and his father. DNA sequencing of the HBA2 gene confirmed the IVS-I-1 mutation in the proband and his mother. This case highlighted the unique interaction of the IVS-I-1 mutation with Hb Adana in a young Malay boy presenting with transfusion-dependent α-thal.

Evaluation of Glucose-6-Phosphate Dehydrogenase stability in stored blood samples

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the commonest cause of neonatal jaundice in Malaysia. Recently, OSMMR2000-D G6PD Assay Kit has been introduced to quantitate the level of G6PD activity in newborns delivered in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). As duration of sample storage prior to analysis is one of the matters of concern, this study was conducted to identify the stability of G6PD enzyme during storage. A total of 188 cord blood samples from normal term newborns delivered at UKMMC were selected for this study. The cord bloods samples were collected in ethylene-diamine-tetra-acetic acid (EDTA) tubes and refrigerated at 2-8 °C. In addition, 32 out of 188 cord blood samples were spotted on chromatography paper, air-dried and stored at room temperature. G6PD enzyme activities were measured daily for 7 days using the OSMMR2000-D G6PD Assay Kit on both the EDTA blood and dried blood samples. The mean value for G6PD activity was compared between days of analysis using Student Paired T-Test. In this study, 172 out of 188 cord blood samples showed normal enzyme levels while 16 had levels corresponding to severe enzyme deficiency. The daily mean G6PD activity for EDTA blood samples of newborns with normal G6PD activity showed a significant drop on the fourth day of storage (p < 0.005) while for samples with severely deficient G6PD activity, significant drop was seen on third day of storage (p = 0.002). Analysis of dried cord blood showed a significant reduction in enzyme activity as early as the second day of storage (p = 0.001). It was also noted that mean G6PD activity for spotted blood samples were lower compared to those in EDTA tubes for all days (p = 0.001). Thus, EDTA blood samples stored at 2-8 °C appeared to have better stability in terms of their G6PD enzyme level as compared to dried blood samples on filter paper, giving a storage time of up to 3 days.

The dental identification of victims of an aircraft accident in Malaysia

On 15 September 1995 a Malaysian Airlines (MAS) Fokker 50 plane plunged while descending and crashed, killing thirty-four passengers aboard. The dental disaster victim identification team comprising dental surgeons from the Dental faculty, University of Malaya; Ministry of Health, Sabah; and the Malaysian Defence Forces played an active role in the identification process. Most of the bodies were badly mutilated, disfigured and severely incinerated. Problems were encountered due to inadequate facilities and space at the mortuary. Difficulties were also encountered during the procurement and deciphering of information from dental records. This disaster has however created greater awareness amongst Malaysians of the important role of forensic odontology in mass disasters.

Bolus or infusion teicoplanin for intravascular catheter associated infections in immunocompromised patients?

An unexpected low efficacy of teicoplanin in the treatment of coagulase negative staphylococcal (CNS) infections on a regional Bone Marrow Transplant (BMT) Unit led to a retrospective study. CNS infections treated with gylcopeptides in BMT patients with in-dwelling central venous lines between May 1990 and May 1995 were reviewed. Efficacy rates of 50% for teicoplanin compared with 80% for vancomycin despite comparable antibiotic susceptibility. Glycopeptides have bactericidal action which is time dependent. Teicoplanin was administered by bolus injection during the study period and it is suggested that this observed difference in efficacy is caused by the short duration of exposure of luminal bacteria.

[Breast cancers and pregnancy. 43 cases reported in the National Oncology Institute between 1985 and 1988]

We report a 4-year retrospective study of 43 cases of breast cancer related to pregnancy and the post-natal period, corresponding to a 4.6% incidence in the breast cancers recorded during the same period. The mean age of our patients was 33 years. The most common reason for the consultation was the tumour. Inflammatory signs were present in 25% of cases and 80% of our patients had palpable under-arm adenopathies. 27% of cases were metastatic from the outset. The timing of treatment was the only parameter to be changed on the basis of age or the continuation of pregnancy or stage of the illness. Termination of pregnancy was carried out in only 2 cases. Recurrences occurred in 70% of cases and the survival median was 18 months. We noted that breast cancer during the perinatal period constitutes a poor prognosis, hence the importance of early diagnosis and care.

Factors influencing the in-vitro sensitivity of Ureaplasma urealyticum to tetracyclines

The sensitivity of 23 strains of Ureaplasma urealyticum to doxycycline was measured by a metabolism-inhibition technique. The minimal inhibitory concentrations were not influenced by using, as inocula in the tests, organisms either directly from the patient or after culture, providing that the numbers of organisms in the inocula were about the same in both. All the strains were sensitive to doxycycline but an apparent increase in the resistance of the cultured organisms occurred when the number, expressed as colour-changing units (ccu), in the inoculum was 10(5) or more/ml. Tests may be undertaken on cultured organisms of U. urealyticum but it is recommended that a standard inoculum of 10(3)-10(4) ccu/ml should be used.

Acute epididymitis: a microbiological and ultrasonographic study

In a prospective study of 24 men (mean age 28.3 years) with acute epididymitis who underwent epididymal aspiration, micro-organisms were detected in 15 (62.5%). Chlamydia trachomatis accounted for 10 (42%) of the cases, being located in both the urethra and epididymis in 5 individuals. Chlamydial serology supported the diagnosis of chlamydial infection, there being a strong correlation between the detection of C. trachomatis and elevated titres of both chlamydial IgG and IgM antibodies. In 4 patients (mean age 55.5 years), Escherichia coli was cultured from both mid-stream urine and epididymal aspirate. Transrectal ultrasound revealed abnormal prostatic scans in 19 patients (79%). These data confirm the aetiological role of C. trachomatis, support the notion that micro-organisms spread intra-canalicularly and suggest that the prostate is also involved in the inflammatory process in acute epididymitis.

Infection of the epididymis by Ureaplasma urealyticum

Ureaplasma urealyticum organisms (ureaplasmas) were isolated from the urethra and epididymal aspirate of a man aged 24 who had acute right sided epididymitis. No other microorganisms were detected, and he had no chlamydial antibody response. A fourfold antibody response to the epididymal ureaplasma isolate was detected by two methods, however, and the patient responded clinically to doxycycline, to which the ureaplasmal isolates were susceptible in vitro. These findings suggest that U urealyticum had a causative role.