Browsing by Author "Esser, Monika"
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- ItemAntibody responses to vaccination among South African HIV-exposed and unexposed uninfected infants during the first 2 years of life(American Society for Microbiology, 2013-01) Reikie, Brian A.; Naidoo, Shalena; Ruck, Candice E.; Slogrove, Amy L.; De Beer, Corena; La Grange, Heleen; Adams, Rozanne C. M.; Ho, Kevin; Smolen, Kinga; Speert, David P.; Cotton, Mark F.; Preiser, Wolfgang; Esser, Monika; Kollmann, Tobias R.HIV-exposed but uninfected (HEU) infants born to HIV-infected mothers from areas in the world with a high burden of infectious disease suffer higher infectious morbidity and mortality than their HIV unexposed uninfected (HUU) peers. Vaccination provides protection from infection. The possibility exists that altered response to vaccination contributes to the higher rate of infection in HEU than in HUU infants. While short-term, cross-sectional studies support this notion, it is unclear whether or not HEU infants develop long-term protective immune responses following theWHOextended program on immunization (EPI). Vaccine-specific antibody responses were compared between HEU and HUU infants from 2 weeks until 2 years of age in a longitudinal South African cohort. Total IgG and antibodies specific for Bordetella pertussis, Haemophilus influenzae type b (Hib), tetanus toxoid, hepatitis B virus (HepB), and measles virus were measured at multiple time points throughout the first 2 years of life. Prevaccine antibodies (maternal antibodies passively acquired) specific for tetanus were lower in HEU than in HUU infants, while prevaccine antibodies to HepB were higher in HEU than in HUU infants. Both groups responded similarly to tetanus, Hib, and HepB vaccination. HEU demonstrated stronger pertussis vaccine responses, developing protective titers 1 year earlier than HUU patients, and maintained higher anti-tetanus titers at 24 months of age. Vaccine-induced antibodies to measles virus were similar in both groups at all time points. Our results suggest that the current EPI vaccination program as practiced in South Africa leads to the development of vaccine-specific antibody responses that are equivalent in HEU and HUU infants. However, our data also suggest that a large fraction of both HEU and HUU South African infants have antibody titers for several infectious threats that remain below the level of protection for much of their first 2 years of life.
- ItemCharacteristics and outcome of children with juvenile dermatomyositis in Cape Town: a cross-sectional study(BioMed Central, 2016-11-11) Okongo, Lawrence Owino; Esser, Monika; Wilmshurst, Jo; Scott, ChristiaanBackground: Juvenile dermatomyositis (JDM) is a rare idiopathic inflammatory childhood myopathy of uncertain aetiology. The demographic and clinical presentation of JDM may differ by race and geographic regions. Few studies have described the characteristics of JDM patients from Africa. Methods: We conducted a retrospective observational study to determine clinical characteristics and outcomes of patients satisfying the Bohan and Peter criteria for probable JDM seen between 2004 and 2013 in three hospitals in Cape Town, South Africa. Results: Twenty five cases were identified: 16 female and 9 male; thirteen (52 %) were of indigenous African, eleven (44 %) mixed and one (4 %) European ancestry. The median ages at disease onset and diagnosis were 6.75 (range 2.0–9.7) and 7.9 (range 3.4–9.75) years respectively. Eleven patients had calcinosis while the mortality was 2/ 25 (8 %). Only 40 % of the patients had clinically inactive disease by PRINTO criteria (modified) at last review. There was no statistically significant difference in racial distribution (p-value = 1), age at disease onset (p-value = 0.87) and disease duration prior to treatment initiation (p-value = 0.75) between patients who had clinically active and inactive disease. Conclusion: The demographic characteristics of children with JDM were similar to that from most other regions of the world with female predominance and similar age at onset. Majority of the patients remained with clinically active disease, which put them at risk of further disease complications. Long term follow up and use of appropriate treatment guidelines may be indicated in management of JDM patients for optimum treatment outcomes.
- ItemEffects of postnatal interventions for the reduction of vertical HIV transmission on infant growth and non-HIV infections : a systematic review(BioMed Central, 2013-12-20) Zunza, Moleen; Mercer, Gareth D.; Thabane, Lehana; Esser, Monika; Cotton, Mark F.Introduction: Guidelines in resource-poor settings have progressively included interventions to reduce postnatal HIV transmission through breast milk. In addition to HIV-free survival, infant growth and non-HIV infections should be considered. Determining the effect of these interventions on infant growth and non-HIV infections will inform healthcare decisions about feeding HIV-exposed infants. We synthesize findings from studies comparing breast to formula feeding, early weaning to standard-duration breastfeeding, breastfeeding with extended antiretroviral (ARV) to short-course ARV prophylaxis, and alternative preparations of infant formula to standard formula in HIV-exposed infants, focusing on infant growth and non-HIV infectious morbidity outcomes. The review objectives were to collate and appraise evidence of interventions to reduce postnatal vertical HIV transmission, and to estimate their effect on growth and non-HIV infections from birth to two years of age among HIV-exposed infants. Methods: We searched PubMed, SCOPUS, and Cochrane CENTRAL Controlled Trials Register. We included randomized trials and prospective cohort studies. Two authors independently extracted data and evaluated risk of bias. Rate ratios and mean differences were used as effect measures for dichotomous and continuous outcomes, respectively. Where pooling was possible, we used fixed-effects meta-analysis to pool results across studies. Quality of evidence was assessed using the GRADE approach. Results and discussion: Prospective cohort studies comparing breast- versus formula-fed HIV-exposed infants found breastfeeding to be protective against diarrhoea in early life [risk ratio (RR)=0.31; 95% confidence interval (CI)=0.13 to 0.74]. The effect of breastfeeding against diarrhoea [hazard ratio (HR)=0.74; 95% CI=0.57 to 0.97] and respiratory infections (HR=0.65; 95% CI=0.41 to 1.00) was significant through two years of age. The only randomized controlled trial (RCT) available showed that breastfeeding tended to be protective against malnutrition (RR=0.63; 95% CI=0.36 to 1.12). We found no statistically significant differences in the rates of non-HIV infections or malnutrition between breast-fed infants in the extended and short-course ARV prophylaxis groups. Conclusions: Low to moderate quality evidence suggests breastfeeding may improve growth and non-HIV infection outcomes of HIV-exposed infants. Extended ARV prophylaxis does not appear to increase the risk for HIV-exposed infants for adverse growth or non-HIV infections compared to short-course ARV prophylaxis.
- ItemExome sequencing identifies a novel TTC37 mutation in the first reported case of Trichohepatoenteric syndrome (THE-S) in South Africa(BioMed Central, 2017-03-14) Kinnear, Craig; Glanzmann, Brigitte; Banda, Eric; Schlechter, Nikola; Durrheim, Glenda; Neethling, Annika; Nel, Etienne; Schoeman, Mardelle; Johnson, Glynis; Van Helden, Paul D.; Hoal, Eileen G; Esser, Monika; Urban, Michael; Moller, MarloBackground Trichohepatoenteric syndrome (THE-S) or phenotypic diarrhoea of infancy is a rare autosomal recessive disorder characterised by severe infantile diarrhoea, facial dysmorphism, immunodeficiency and woolly hair. It was first described in 1982 in two infants with intractable diarrhoea, liver cirrhosis and abnormal hair structure on microscopy. We report on two siblings from a consanguineous family of Somali descent who, despite extensive clinical investigation, remained undiagnosed until their demise. The index patient died of fulminant cytomegalovirus pneumonitis at 3 months of age. Methods Whole exome sequencing (WES) was performed on a premortem DNA sample from the index case. Variants in a homozygous recessive state or compound heterozygous state were prioritized as potential candidate variants using TAPER™. Sanger sequencing was done to genotype the parents, unaffected sibling and a deceased sibling for the variant of interest. Results Exome sequencing identified a novel homozygous mutation (c.4507C > T, rs200067423) in TTC37 which was confirmed by Sanger sequencing in the index case. The identification of this mutation led to the diagnosis of THE-S in the proband and the same homozygous variant was confirmed in a male sibling who died 4 years earlier with severe chronic diarrhoea of infancy. The unaffected parents and sister were heterozygous for the identified variant. Conclusions WES permitted definitive genetic diagnosis despite an atypical presentation in the index case and suggests that severe infection, likely secondary to immunodeficiency, may be a presenting feature. In addition definitive molecular diagnosis allows for genetic counseling and future prenatal diagnosis, and demonstrates the value of WES for post-mortem diagnosis of disorders with a non-specific clinical presentation in which a Mendelian cause is suspected.
- ItemHuman whole genome sequencing in South Africa(Nature, 2021-01) Glanzmann, Brigitte; Jooste, Tracey; Ghoor, Samira; Gordon, Richard; Mia, Rizwana; Mao, Jun; Li, Hao; Charls, Patrick; Douman, Craig; Kotze, Maritha J.; Peeters, Armand V.; Loots, Glaudina; Esser, Monika; Tiemessen, Caroline T.; Wilkinson, Robert J.; Louw, Johan; Gray, Glenda; Warren, Robin M.; Moller, Marlo; Kinnear, CraigThe advent and evolution of next generation sequencing has considerably impacted genomic research. Until recently, South African researchers were unable to access affordable platforms capable of human whole genome sequencing locally and DNA samples had to be exported. Here we report the whole genome sequences of the first six human DNA samples sequenced and analysed at the South African Medical Research Council’s Genomics Centre. We demonstrate that the data obtained is of high quality, with an average sequencing depth of 36.41, and that the output is comparable to data generated internationally on a similar platform. The Genomics Centre creates an environment where African researchers are able to access world class facilities, increasing local capacity to sequence whole genomes as well as store and analyse the data.
- ItemJuvenile idiopathic arthritis in two tertiary centres in the Western Cape, South Africa(BioMed Central, 2012-10) Weakley, Kate; Esser, Monika; Scott, ChristiaanBACKGROUND: Juvenile idiopathic arthritis (JIA) is a disease that shows wide variations between differing populations. Since the recent international consensus on classification criteria, JIA has been widely described in many countries and population groups. There has been almost no data that describes JIA in an African, specifically Sub-Saharan African, setting. Therefore, the aim of this study is to describe disease characteristics, disease course, and functional disability in two tertiary centres in the Western Cape, South Africa and compare the findings to other JIA populations. Methods: Eighty-six children were recruited during random clinic visits to rheumatology clinics at Tygerberg and Groote Schuur Hospital between April 2010 and April 2011. Children were diagnosed using International League of Associations for Rheumatology (ILAR) 2001 classification criteria. Consent was obtained and medical records examined. The Childhood Health Assessment Questionnaires (CHAQ) and visual analogue scales (VAS) for pain and general well-being were completed and all children were examined by a researcher in conjunction with a paediatric rheumatologist. HIV status as well as tuberculosis disease and treatment were investigated. Results: A total of 86 children were enrolled. Eight children were excluded (2 HIV arthropathy, 1 TB arthritis, 1 SLE, 4 with insufficient data), leaving a total of 78 patients. There was an equal female to male ratio-39 males and 39 females. There were 6 systemic JIA patients (7.69%), 17 persistent oligoarthritis (21.79%), 4 extended oligoarthritis (5.12%), 11 polyarthritis rheumatoid factor (RF) positive (14.10%), 21 polyarthritis RF negative (26.9%), 1 psoriatic arthritis (1.28%), and 18 enthesitis-related arthritis (23%). The median CHAQ for the group was 0.5 (IQR 0.1-1.25), the median VAS for pain was 18 mm (IQR 4–42) and median VAS for general well-being was 25 mm (IQR 3–49). Enthesitis-related arthritis and polyarthritis disease subtypes in this South African population may be more common than seen in JIA populations described in northern Europe, India, United Kingdom, and Turkey. Conclusion: This Western Cape South African JIA population appears to have a different profile of JIA than what has been described elsewhere. Enthesitis-related arthritis and polyarthritis disease subtypes appear to be more prevalent. There are also significant challenges in this setting such as later presentation to pediatric rheumatologists, different disease characteristics, and variable disease courses.
- ItemThe neuromyelitis optica presentation and the aquaporin-4 antibody in HIV-seropositive and seronegative patients in KwaZulu-Natal, South Africa(AOSIS Publishing, 2017) Bhigjee, Ahmed I.; Moodley, Anandan A.; Roos, Izanne; Wells, Cait-Lynn; Ramdial, Pratistadevi; Esser, MonikaBackground: The association of the anti-aquaporin-4 (AQP-4) water channel antibody with neuromyelitis optica (NMO) syndrome has been described from various parts of the world. There has been no large study describing this association from southern Africa, an HIV endemic area. HIV patients often present with visual disturbance or features of a myelopathy but seldom both either simultaneously or consecutively. We report our experience of NMO in the era of AQP-4 testing in HIV-positive and HIV-negative patients seen in KwaZulu-Natal, South Africa. Methods: A retrospective chart review was undertaken of NMO cases seen from January 2005 to April 2016 in two neurology units serving a population of 7.1 million adults. The clinical, radiological and relevant laboratory data were extracted from the files and analysed. Results: There were 12 HIV-positive patients (mean age 33 years), 9 (75%) were women and all 12 were black patients. Of the 17 HIV-negative patients (mean age 32 years), 15 (88%) were women and 10 (59%) were black people. The clinical features in the two groups ranged from isolated optic neuritis, isolated longitudinally extensive myelitis or combinations. Recurrent attacks were noted in six HIV-positive patients and six HIV-negative patients. The AQP-4 antibody was positive in 4/10 (40%) HIV-positive patients and 11/13 (85%) HIV-negative patients. The radiological changes ranged from longitudinal hyperintense spinal cord lesions and long segment enhancing lesions of the optic nerves. Three patients, all HIV-positive, had tumefactive lesions with incomplete ring enhancement. Conclusion: This study confirms the presence of AQP-4-positive NMO in southern Africa in both HIV-positive and HIV-negative patients. The simultaneous or consecutive occurrence of optic neuritis and myelitis in an HIV-positive patient should alert the clinician to test for the AQP-4 antibody. It is important to recognise this clinical syndrome as specific therapy is available. We further postulate that HIV itself may act as a trigger for an autoimmune process.
- ItemOntogeny of toll-like receptor mediated cytokine responses of South African infants throughout the first year of life(Public Library of Science, 2012-09-13) Reikie, Brian A.; Adams, Rozanne C. M.; Ruck, Candice E.; Ho, Kevin; Leligdowicz, Aleksandra; Pillay, Santoshan; Naidoo, Shalena; Fortuno III, Edgardo S.; De Beer, Corena; Preiser, Wolfgang; Cotton, Mark F.; Speert, David P.; Esser, Monika; Kollmann, Tobias R.The first year of life represents a time of marked susceptibility to infections; this is particularly true for regions in sub-Saharan Africa. As innate immunity directs the adaptive immune response, the observed increased risk for infection as well as a suboptimal response to vaccination in early life may be due to less effective innate immune function. In this study, we followed a longitudinal cohort of infants born and raised in South Africa over the first year of life, employing the most comprehensive analysis of innate immune response to stimulation published to date. Our findings reveal rapid changes in innate immune development over the first year of life. This is the first report depicting dramatic differences in innate immune ontogeny between different populations in the world, with important implications for global vaccination strategies.
- ItemOptimising automation of a manual enzyme-linked immunosorbent assay(AOSIS Publishing, 2012-10) De Beer, Corena; Esser, Monika; Preiser, WolfgangObjective: Enzyme-linked immunosorbent assays (ELISAs) are widely used to quantify immunoglobulin levels induced by infection or vaccination. Compared to conventional manual assays, automated ELISA systems offer more accurate and reproducible results, faster turnaround times and cost effectiveness due to the use of multianalyte reagents. Design: The VaccZyme™ Human Anti-Haemophilus influenzae type B (Hib) kit (MK016) from The Binding Site Company was optimised to be used on an automated BioRad PhDTM system in the Immunology Laboratory (National Health Laboratory Service) in Tygerberg, South Africa. Methods: An automated ELISA system that uses individual well incubation was compared to a manual method that uses whole-plate incubation. Results: Results were calculated from calibration curves constructed with each assay. Marked differences in calibration curves were observed for the two methods. The automated method produced lower-than-recommended optical density values and resulted in invalid calibration curves and diagnostic results. A comparison of the individual steps of the two methods showed a difference of 10 minutes per incubation cycle. All incubation steps of the automated method were subsequently increased from 30 minutes to 40 minutes. Several comparative assays were performed according to the amended protocol and all calibration curves obtained were valid. Calibrators and controls were also included as samples in different positions and orders on the plate and all results were valid. Conclusion: Proper validation is vital before converting manual ELISA assays to automated or semi-automated methods.
- ItemPrimary immunodeficiency diseases(Health and Medical Publishing Group (HMPG), 2012-08) Buldeo, Suvarna; Suchard, Melinda; Esser, MonikaPrimary immunodeficiency diseases (PIDs) are a group of disorders with defects in the development or function (or both) of the immune system. Most PIDs originate from mutations in single genes, but polygenic forms do occur.1 The global prevalence of PIDs varies between 0.3 and 12 per 100 000 population, and is higher in areas with high rates of consanguinity.2 The prevalence in South Africa is unknown, but according to prevalence data reported from the PID register,3 these diseases are either missed or not reported. The possible reasons for under-diagnosis are that patients presenting with recurrent, persistent, severe or even unusual infections are treated without investigating the underlying cause, or the diagnosis is missed in the face of the overwhelming burden of similar clinical presentations of infectious diseases such as HIV and tuberculosis. Early diagnosis is important as therapeutic options are available to treat and prevent long-term sequelae such as bronchiectasis, which will improve quality of life and decrease mortality. Basic laboratory assays to screen for PIDs are available throughout South Africa but the threshold for investigation among healthcare workers is high. This review aims to increase the clinical suspicion of PIDs in South Africa and provide an approach to the diagnosis and management.
- ItemToxoplasma gondii seroprevalence studies on humans and animals in Africa(Medpharm Publications, 2014) Hammond-Aryee, Kenneth Nii Ofei; Esser, Monika; Van Helden, Paul D.Background: Toxoplasmosis is a disease caused by Toxoplasma gondii, which can infect nearly all mammalian and avian species. Approximately 25% of the global human population is thought to be infected. Interest in toxoplasmosis has surged since it was discovered that with the onset of acquired immune deficiency syndrome, acute toxoplasmosis could induce cranial calcification. The ensuing encephalitis can be fatal. The African human immunodeficiency virus (HIV) epidemic, increasing levels of other immunosuppressive infections (such as tuberculosis), poor sanitation practices and lack of monitoring of at-risk populations point to a predicament that may be underrated. Objective: The objective was to review the available body of research on the seroepidemiology of T. gondii in Africa, in order to establish existing prevalence trends and to draw attention to available information on the pathogen in Africa. Method: The National Center for Biotechnology Information, Google Scholar and ToxoDB databases were searched for peer-reviewed articles that focus specifically on seroprevalence studies of T. gondii in Africa up until the 2012 year end. Results: Seroprevalence rates on the continent are high in humans and animals. There is a geographical trend of decreasing seroprevalence from the northern to the southern, and from the western to the eastern, regions of the continent. Most seroprevalence studies on humans were reported between 1981 and 2000. Conclusion: There is a need for further and more consolidated information on the prevalence of T. gondii in Africa, in order to address morbidity and mortality from opportunistic but treatable diseases, such as toxoplasmosis in the ongoing HIV pandemic, and to improve the lives of the African population.