African Journal of Laboratory Medicine最新文献

Background: β-thalassaemia is considered rare in Africa; however, recent screening-based studies suggest a β-thalassaemia trait prevalence of 6% - 10% among individuals with sickle cell disease (SCD) and up to 25% in those without SCD. Co-inheritance with SCD may modify disease severity, highlighting the need for molecular confirmation.

Objective: To ascertain the prevalence and genetic basis of β-thalassaemia trait in Nigerians with and without SCD.

Methods: We recruited 260 participants (130 per group; aged 3 years - 69 years, median [interquartile range] = 16 [9-29]). Haemoglobin fractions were analysed using high-performance liquid chromatography, and full blood counts were obtained. A 1.6 kb region of the β-globin gene was amplified and sequenced by Sanger sequencing. Variants were annotated and haplotypes constructed. An additional 26 samples from a separate SCD cohort were also genotyped.

Results: Molecular analysis revealed a β-thalassaemia trait prevalence of < 1% in both groups, contrasting with recent screening-based reports. In addition to sickle cell, haemoglobin C, and β-thalassaemia mutations, eight other variants were identified, three of which were unique to SCD patients and in linkage disequilibrium. Sickle cell and haemoglobin C mutations occurred on the major ancestral haplotype, whereas the only β-thalassaemia mutation detected (rs33915217C>A) was associated with a minor ancestral haplotype atypical of Africa. Two rare variants (rs537944366T>C and rs33915217C>A) are reported for the first time in the Yoruba population.

Conclusion: These findings indicate a low prevalence of β-thalassaemia trait in Nigeria and underscore the need to re-evaluate diagnostic approaches in African populations for optimal clinical management of SCD and other anaemias.

What this study adds: This study provides the first molecular confirmation of the low prevalence of β-thalassaemia trait in the Yoruba population. It identifies two rare variants, including a β-thalassaemia mutation on a minor, atypical haplotype, and highlights the limitations of high-performance liquid chromatography, underscoring the importance of genetic testing for accurate diagnosis.

Background: Multiple sclerosis (MS) is a neurodegenerative central nervous system disorder causing axonal damage and disability. Relapses develop over hours or days and then subside over weeks. Disease-modifying drugs (DMDs) influence disease activity. Interferon beta-1A (IFN-b-1A) is a widely used first-line treatment for relapsing remitting MS (RRMS) that reduces central nervous system inflammation. Fingolimod affects lymphocyte trafficking. B-cell therapy (rituximab) depletes circulating CD20+ B cells in cerebrospinal fluid, but their specific effects in RRMS remain limited.

Objective: The aim of the present study was to evaluate the effect of DMDs such as IFN-b-1A, fingolimod and rituximab on neurofilament light chain (NFL) and chitinase 3-like 1 (CHI3L1) serum levels, and some biomarkers of plasmacytoid dendritic cells (pDCs) in RRMS patients.

Methods: Thirty healthy controls and 44 RRMS patients actively receiving their DMDs, were recruited into this study. Patients were divided into three groups according to DMDs type: Group 1 (n = 17) received IFN-b-1A, Group 2 (n = 20) received fingolimod, and Group 3 (n = 7) received rituximab. Patients of all ages and both sexes were included.

Results: Serum NFL (84.1% sensitivity and 60.0% specificity) and CHI3L1 (90.9% sensitivity and 73.0% specificity) levels were higher in patients than in controls (p ≤ 0.001), with higher levels of NFL in the B-cell therapy group compared with IFN-b-1A (p ≤ 0.001) and fingolimod (p = 0.005), and higher levels of CHI3L1 in the B-cell group compared to IFN-b-1A (p = 0.001) and fingolimod (p = 0.015). Plasmacytoid dendritic cells showed no difference in tolerogenic and migratory function between the DMDs groups.

Conclusion: Disease-modifying drug type (IFN-b-1A, fingolimod, and B-cell therapy) impacts NFL and CHI3L1 serum levels as drug response biomarkers and relates to clinical data of MS patients, but has no diverse impact on the migratory and tolerogenic function of pDCs.

What this study adds: The serum NFL and CHI3L1 need to be validated as drug response biomarkers in RRMS patients, evaluating the DMDs' effect on immunocellular level by studying migratory and tolerogenic functions of pDCs.

Background: Blood transfusion is a lifesaving procedure performed across all healthcare levels in Tanzania. Despite significant investment in blood collection and screening, hospital transfusion practices have received less attention. With haemovigilance systems still in development, the understanding of pre-transfusion testing quality remains limited.

Objective: This study aimed to evaluate hospital blood bank practices in conducting pre-transfusion procedures prior to issuing blood for transfusion.

Methods: This descriptive cross-sectional study was conducted from January 2024 to March 2024 in 31 referral hospitals in Tanzania. Data on facility characteristics, testing methods, staffing, and equipment were collected through a validated questionnaire. Data were analysed using STATA version 18. Descriptive statistics were used to present key findings whereby continuous variables were presented as means, and categorical variables were presented as frequencies and percentages.

Results: Among 31 participating facilities, ABO and Rhesus blood group systems typing and cross-matching were universally available (100%), while antibody screening was available in 13 out of 31 facilities (42.0%). Two out of 31 facilities (6.5%) used the less sensitive tile method for ABO typing. Critical reagents including Anti-D (immunoglobulin G), Anti-Human Globulin, and polythene tubes were available in only 21 out of 31 facilities (67.7%). While all facilities had standard operating procedures (SOPs) for basic tests, blood warming SOPs were available in 9 (29.0%) and fresh frozen plasma thawing SOPs were available in 14 (45.2%) out of 31 facilities.

Conclusion: Significant gaps exist in pre-transfusion testing capabilities, SOPs, and essential reagents in Tanzanian referral hospital blood banks. Addressing these shortcomings is crucial for improving transfusion safety and strengthening haemovigilance.

What this study adds: This study presents the first national audit of hospital blood bank practices in Tanzania, highlighting major gaps in antibody screening and cross-matching, resource shortages such as key reagents, and quality management deficiencies. It offers evidence-based, phased recommendations to strengthen pre-transfusion testing and improve safety in resource-limited settings.

Background: Age, gender, and mutation type are key risk factors for myeloproliferative neoplasms (MPNs). Africa remains under-represented in global cancer statistics due to limited population-based genomic data.

Objective: To determine the frequency and demographic associations of common MPN-related genetic abnormalities in the South African population.

Methods: A retrospective cross-sectional analysis of cytogenetic results for Janus kinase-2 p.V617F (JAK-2 p.V617F), Janus kinase-2 exon 12 (JAK-2 exon 12), calreticulin (CALR), myeloproliferative leukaemia virus oncogene (MPL), and breakpoint cluster region-Abelson kinase 1 (BCR::ABL1) was conducted from 01 January 2018 to 31 May 2023. Data were retrieved from the National Health Laboratory Service and analysed for associations with age and gender using Fisher's Exact Test or Pearson's Chi-Square Test (p < 0.05).

Results: A total of 8934 patient records were analysed; 58% were male patients and 42% female patients, with a mean age of 50 ± 17 years. Among sequence variant changes, 18.2% of MPN cases were positive for BCR::ABL1, 8.5% for JAK-2 p.V617F, 0.5% for CALR, 0.04% for MPL, and none for JAK-2 exon 12. BCR::ABL1 showed equal sex distribution, while JAK-2 p.V617F increased with age and showed slight female predominance (p = 0.002). CALR and MPL frequencies were too low for meaningful association testing.

Conclusion: BCR::ABL1 was the most frequent abnormality, especially in younger age groups, whereas JAK-2 p.V617F was linked to increasing age and female predominance.

What this study adds: MPN genetic testing in South Africa predominantly targeted male patients (ratio 1.4:1). BCR::ABL1 was the most common abnormality, particularly in individuals aged 18 to 49 years, while JAK-2 p.V617F showed a slight female predominance (1:1.2).

Background: Despite progress toward the Joint United Nations Programme on HIV/AIDS (UNAIDS) 95-95-95 targets, Zambia faces persistent gaps in HIV testing coverage. The Ministry of Health implemented blood-based HIV self-testing (HIVST) to improve accessibility. This study evaluated the CheckNOW™ HIVST kit's usability in Lusaka province health facilities.

Objective: To determine usability, awareness and user-friendliness of the CheckNOW™ HIVST among Zambian adults.

Methods: We conducted a cross-sectional study from 04 September 2023 - 22 September 2023 across four high-volume healthcare facilities. A total of 323 CheckNOW™ HIVST kits were distributed, with 316 consenting adults successfully enrolled in the study. Data were collected through structured questionnaires administered via face-to-face interviews following test completion, capturing information on socio-demographics, HIV testing history and user perception of the self-testing process. Descriptive statistics were employed for data analysis.

Results: Among 316 participants, 56.3% (178/316) were female, and 41.5% (131/316) were aged 25-34 years. The majority (95.0%, 300/316; p < 0.001) found the CheckNOW™ kit easy to use, while 65.0% (206/316) had prior awareness of HIVST. Additionally, 83.6% (264/316; p < 0.001) followed the test instructions correctly and independently. A high proportion (98.7%, 312/316; p < 0.001) expressed willingness to test again, and 99.7% (315/316; p < 0.001) would recommend it to others.

Conclusion: The CheckNOW™ blood-based HIVST kit demonstrated high usability and ease of use, supporting its potential to expand HIV testing coverage in Zambia. However, increased awareness efforts are necessary to maximise uptake and ensure broader accessibility.

What this study adds: This study provides the first evidence that blood-based HIV self-testing is feasible and acceptable within Zambian clinical settings. It offers a critical new strategy to expand testing coverage and reach key populations by integrating self-testing into routine health services.

Background: Following a major service disruption across the National Health Laboratory Service, backlogged HIV viral load (VL) specimens from Limpopo province were rerouted to Groote Schuur Hospital (GSH) laboratory in the Western Cape province. During this time, an increase in low-level viraemia (LLV; 50 copies/mL - 1000 copies/mL) was observed at the GSH laboratory, raising concerns about possible pre-analytical and analytical issues, including compromised specimen quality and possible contamination.

Objective: To determine whether the observed increased LLV was due to analytical errors (e.g. contamination), pre-analytical factors such as prolonged turnaround times (TAT), or underlying epidemiological differences.

Methods: HIV VL data from 2023-2024 for Limpopo and the Western Cape were analysed using Python. Viral load results were grouped into predefined categories and compared. Turnaround times were plotted and Thembisa model estimates were used to assess HIV prevalence and antiretroviral therapy (ART) coverage. Longitudinal patient-level analysis evaluated VL trends as a proxy for adherence. In addition, quality control data were evaluated at testing sites.

Results: Limpopo specimens showed higher LLV (20%) and lower viral suppression (< 50 copies/mL) at 70%, compared to Western Cape (13% LLV, 81% suppression), where follow-up and suppression outcomes were also higher. No clear evidence indicated that extended TAT or potential instrument contamination affected VL results significantly.

Conclusion: The increase in LLV at GSH was linked primarily to processing specimens from Limpopo, highlighting regional differences in HIV VL result distributions. These differences probably reflect variations in ART access and adherence, rather than laboratory-related issues such as delayed TAT, sample quality, or contamination.

What this study adds: This study shows how province-specific HIV result patterns correlate with ART adherence, using a Python script to assess serial VLs and follow-up suppression. It demonstrates the value of routine data analysis in monitoring high-throughput HIV VL tests, which are often auto-released without pathologist oversight.

Background: Tigecycline, an antibiotic effective against multidrug-resistant bacteria (MDRB), remains inaccessible in Burkina Faso's hospitals for urgent care. Given the resulting therapeutic challenges and mortality in emergency services, evidence-based study of tigecycline's efficacy on local bacterial clinical isolates is necessary before recommending its use.

Objective: This study aimed to evaluate the activity of tigecycline on MDRB isolates at the Sourô Sanou University Teaching Hospital laboratory, Burkina Faso.

Methods: This was a cross-sectional study with prospective and consecutive sampling of MDRBs. The latter included extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant strains (CRS), and methicillin-resistant Staphylococcus aureus (MRSA), which were isolated from urine, blood, pus and puncture fluids between 01 June 2022 and 31 August 2022. Antimicrobial susceptibility testing was conducted using the modified Kirby-Bauer method, and the results were interpreted according to the standard set by the European Committee on Antimicrobial Susceptibility Testing in 2021.

Results: A total of 117 MDRBs, including 93 Enterobacterales, 15 carbapenem-resistant Acinetobacter baumannii (CRAB), and 9 MRSAs were collected. The proportion of ESBL-E was 58% (68/117), followed by CRS (34%, 40/117) and MRSA (8%, 9/117). The activity of tigecycline was 95.5% (43/45) on ESBL-E, 72.5% (29/40) on CRS (including 10/15 CRAB), and 89% (8/9) on MRSA.

Conclusion: The activity of tigecycline was highly effective on ESBL-E, carbapenem resistant Enterobacterales and MRSA, and moderate on CRAB.

What this study adds: This was the first report on the evaluation of tigecycline activity on MDRBs in Burkina Faso. This non-marketed antibiotic in Burkina Faso could represent an alternative to spare carbapenems in the treatment of ESBL-E infections, and a last resort antibiotic against susceptible CRS infections in Burkina Faso's hospitals.

Background: Altered apolipoproteins and high-density lipoprotein (HDL) phospholipids are linked to premature atherosclerotic cardiovascular disease (ASCVD).

Objective: This study investigated associations between plasma apolipoprotein A1, apolipoprotein B, HDL phospholipids, and ASCVD risk in Nigeria, assessing their potential as early diagnostic markers.

Methods: This cross-sectional case-control study was conducted from November 2021 to November 2022 at Lagos State University Teaching Hospital in Nigeria. Atherosclerotic cardiovascular disease patients and healthy controls were randomly selected. The plasma apolipoprotein A1 and B levels were determined via a sandwich enzyme-linked immunosorbent assay, and the lipid profile was measured via spectrophotometry. Statistical analyses included t-tests, analysis of variance, analysis of covariance, and Pearson's correlation.

Results: In total, 172 confirmed ASCVD patients (mean age: 54.01 ± 8.70 years) and 55 healthy controls (mean age: 44.55 ± 11.60 years) were included in the analyses. Compared with the control values, ASCVD patients showed significantly elevated apolipoprotein B, apolipoprotein B/A1 ratio, atherogenic lipid indices, total cholesterol, low-density lipoprotein cholesterol, non-HDL cholesterol, and triglycerides (p ≤ 0.001). In contrast, plasma HDL phospholipids, apolipoprotein A1, and HDL cholesterol were markedly lower (p ≤ 0.001).

Conclusion: These findings indicate that altered apolipoproteins and HDL phospholipids are associated with premature ASCVD risk, with the apolipoprotein B/A1 ratio emerging as a superior marker for disease stratification.

What this study adds: This study identifies the apolipoprotein B/A1 ratio as a strong early marker of ASCVD risk in Nigeria.

Background: Toxoplasmosis is a parasitic zoonosis of major importance, particularly during pregnancy because of the risk of maternal-foetal transmission.

Objective: The aim of the study was to estimate the seroprevalence of Toxoplasma gondii in pregnant women at the University Hospital of Cocody and to describe IgG/IgM serological profiles.

Methods: We conducted a retrospective cross-sectional study from April 2022 to March 2023 at the immunology laboratory of the University Hospital of Cocody. Toxoplasma gondii-specific IgG and IgM antibodies were measured by electrochemiluminescence immunoassay and then interpreted according to serological profiles. Chi-square test was used to assess the association between IgM positivity and pregnancy trimester.

Results: Out of 200 pregnant women, previous infection was observed in 45.0% (IgG⁺/IgM^-), current infection in 4.0% (IgG⁺/IgM⁺), recent infection in 5.5% (IgG-/IgM⁺), and no infection in 45.5% (IgG^-/IgM^-). Of the women, 83% were tested after the first trimester. The proportion of recent infections (IgM⁺) was higher in the first trimester (17.6%) than in the second (8.2%) and third (7.4%) trimesters, with no statistically significant difference (p = 0.22).

Conclusion: The seroprevalence of toxoplasmosis remains high, with a non-negligible proportion of women presenting recent or current infection. Late initiation of screening highlights the need for strengthened strategies, including early screening, targeted antenatal education and better access to diagnostic tools to reduce the risk of transmission.

What this study adds: This study provides updated data on the seroprevalence of gestational toxoplasmosis in Côte d'Ivoire. Thus, it reinforces the need for early screening and targeted health awareness campaigns.

Background: Infection prevention and control (IPC) practices are crucial for protecting patients and healthcare workers (HCWs), especially during the coronavirus disease 2019 (COVID-19) pandemic. This crisis has underscored the importance of IPC strategies in understanding health system readiness and strengthening preparedness for future pandemics.

Objective: This study investigated healthcare personnel's IPC knowledge, adherence to safety policies, and implementation of IPC procedures in COVID-19 treatment centres across Nigeria.

Methods: A cross-sectional, multicentre study was conducted among 113 respondents, that is, 57 HCWs and 56 volunteers, from 23 June 2020 to 15 March 2021. An electronic questionnaire adapted from validated instruments was used.

Results: Out of 113 respondents, 69 (61%) demonstrated good IPC practices, with high adherence (n = 105, 92.9%) to face mask usage and hand hygiene. Only 50 (44.2%) reported receiving basic training on IPC. Although personal protective equipment (PPE) was available, 25% did not consistently wear full PPE when attending to COVID-19 patients. Most HCWs (105; 93%) opposed testing patients without consent, and 100 (88.5%) affirmed the availability of standardised IPC protocols. No significant association was observed between age, gender, years of experience, and IPC compliance (p-values: 0.097, 0.287, and 0.699). Interestingly, 33 (29.2%) HCWs with less than 10 years of experience exhibited better IPC practices. Facility policies such as confidentiality and non-discrimination were mostly upheld, with 90 (79.6%) participants agreeing that discriminatory practices should have consequences.

Conclusion: While face mask use and hand hygiene compliance were high, gaps remained in IPC training and consistent use of full PPE. Strengthening training, IPC knowledge, policy standardisation, and resource equity is important for stronger IPC compliance during health emergencies.

What this study adds: The study identified key factors supporting future pandemic preparedness by examining the control and preventive strategies implemented at various CTCs in Nigeria. It also emphasised the need for standardised policies, which are essential for building resilient healthcare systems during public health crises.