Riette du Toit

Prof. Riette du Toit

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Research Focus & Metrics

Academic Career Length

34Years (1993-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 July 2022 in Rheumatology
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RTRiette du Toit
Riette du Toit
SKSumanth Karamchand
Sumanth Karamchand
ADAnton F Doubell
Anton F Doubell
HRHelmuth Reuter
Helmuth Reuter
PHPhillip G Herbst
Phillip G Herbst
Lupus myocarditis (LM) is a potentially fatal manifestation of SLE, occurring in 5–10% of patients. Clinical manifestations may vary from an unexplained tachycardia to fulminant congestive cardiac failure (CCF). With no single clinical or imaging modality being diagnostic, a rational and practical approach to the patient presenting with possible LM is essential. Markers of myocyte injury (including troponin I and creatine kinase) may be unelevated and do not exclude a diagnosis of LM. Findings on ECG are non-specific but remain essential to exclude other causes of CCF such as an acute coronary syndrome or conduction disorders. Echocardiographic modalities including wall motion abnormalities and speckle tracking echocardiography may demonstrate regional and/or global left ventricular dysfunction and is more sensitive than conventional echocardiography, especially early in the course of LM. Cardiac magnetic resonance imaging (CMRI) is regarded as the non-invasive diagnostic modality of choice in myocarditis. While more sensitive and specific than echocardiography, CMRI has certain limitations in the context of SLE, including technical challenges in acutely unwell and uncooperative patients, contraindications to gadolinium use in the context of renal impairment (including lupus nephritis) and limited literature regarding the application of recommended diagnostic CMRI criteria in SLE. Both echocardiography as well as CMRI may detect subclinical myocardial dysfunction and/or injury of which the clinical significance remains uncertain. Considering these challenges, a combined decision-making approach by rheumatologists and cardiologists interpreting diagnostic test results within the clinical context of the patient is essential to ensure an accurate, early diagnosis of LM.

15 February 2011 in The Journal of Rheumatology
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RTRiette du Toit
Riette du Toit
DWDavid Whitelaw
David Whitelaw
JTJantjie J. Taljaard
Jantjie J. Taljaard
LPLisa du Plessis
Lisa du Plessis
MEMonika Esser
Monika Esser
Objective.: To determine the prevalence and specificity of anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factor (RF) for rheumatoid arthritis (RA) in human immunodeficiency virus (HIV) infection and to evaluate the effect of immune reconstitution on these markers.Methods.: Patients with advanced HIV infection without arthritis were enrolled. CD4+ T lymphocyte counts (CD4), anti-CCP, and RF were determined before initiating antiretroviral therapy (ART) and repeated after 6 months. Results were compared to those of healthy controls. Patients were followed for the development of RA for 1 year.Results.: Sixty patients and 26 controls were studied. Six-month followup results were available on 49 patients. Mean (SD) levels of anti-CCP were higher in patients with HIV compared to controls: respectively, 9.50 (11.41) versus 0.80 (1.32) units (p < 0.001). Mean (SD) levels decreased to 4.85 (8.12) units (p = 0.006) after 6 months of ART (HIV-infected group). Fifteen percent of patients initially tested positive for anti-CCP, 4% after 6 months versus no controls (p = 0.031). Forty-seven percent of patients initially tested positive for RF, 18% after 6 months versus 8% of controls (p < 0.001). Decreases in RF and anti-CCP after ART were accompanied by increased mean (SD) CD4: from 129 (56) to 278 (140) cells/mm3 (p < 0.001). Anti-CCP and RF positivity was not associated with the development of RA.Conclusion.: Increased titers of anti-CCP and RF occur in advanced HIV infection. Although more specific than RF, before immune reconstitution, anti-CCP is an unreliable diagnostic marker for RA and does not necessarily predict future RA. After immune reconstitution, the specificity of anti-CCP approaches that of a control group.

11 July 2016 in Lupus
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RTRiette du Toit
Riette du Toit
PHPhilip George Herbst
Philip George Herbst
ARA van Rensburg
A van Rensburg
LPL M du Plessis
L M du Plessis
HRH Reuter
H Reuter
ADAnton Frans Doubell
Anton Frans Doubell
African American ethnicity is independently associated with lupus myocarditis compared with other ethnic groups. In the mixed racial population of the Western Cape, South Africa, no data exists on the clinical features/outcome of lupus myocarditis. The objective of this study was to give a comprehensive description of the clinical features and outcome of acute lupus myocarditis in a mixed racial population. Clinical records (between 2008 and 2014) of adult systemic lupus erythematosus (SLE) patients at a tertiary referral centre were retrospectively screened for a clinical and echocardiographic diagnosis of lupus myocarditis. Clinical features, laboratory results, management and outcome were described. Echocardiographic images stored in a digital archive were reanalysed including global and regional left ventricular function. A poor outcome was defined as lupus myocarditis related mortality or final left ventricular ejection fraction (LVEF) 90% of patients. LVEF improved from 35% to 47% (p = 0.023) and wall motion score from 1.88 to 1.5 (p = 0.017) following treatment. Overall mortality was high (12/28): five patients (17.9%) died due to lupus myocarditis (bimodal pattern). Patients who died of lupus myocarditis had a longer duration of SLE (p = 0.045) and a lower absolute lymphocyte count (p = 0.041) at diagnosis. LVEF at diagnosis was lower in patients who died of lupus myocarditis (p = 0.099) and in those with a persistent LVEF < 40% (n = 5; p = 0.046). This is the largest reported series on lupus myocarditis. The mixed racial population had a similar prevalence, but higher mortality compared with other ethnic groups (internationally published literature). Patients typically presented with high SLE disease activity and the majority had concomitant lupus nephritis. Lymphopenia and low LVEF at presentation were of prognostic significance, associated with lupus myocarditis related mortality or a persistent LVEF < 40%.

22 November 2020 in Rheumatology
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RTRiette du Toit
Riette du Toit
HRHelmuth Reuter
Helmuth Reuter
GWGerhard Walzl
Gerhard Walzl
CSCandice Snyders
Candice Snyders
NCNovel N Chegou
Novel N Chegou
ADAnton F Doubell
Anton F Doubell
Objectives: To identify cytokines, markers of endothelial activation [soluble vascular cell adhesion molecule-1 (sVCAM-1)] and myocyte strain [soluble ST2 (sST2)] associated with myocardial injury (MInj) in SLE, classified by cardiac magnetic resonance (CMR) criteria.Methods: CMR was performed on patients with SLE, identifying stages of MInj (inflammation and necrosis or fibrosis). Data captured included: clinical assessment, laboratory and serological analyses, cytokine (IL-1β, IL-1Ra, IL-2, IL-6, IL-10, IL-17, IL-18, TNF-alpha), sVCAM-1 and sST2 levels. Cytokines were compared with regard to SLE features and evidence of CMR MInj. Predictors of CMR MInj were determined through regression analyses.Results: Forty-one patients with high disease activity (SLEDAI-2K: 13; IQR: 3–17) were included. SLE features included: LN (n = 12), neurolupus (n = 6) and clinical lupus myocarditis (LM) (n = 6). Nineteen patients had CMR evidence of MInj. Patients with a SLEDAI-2K ≥ 12 had higher sVCAM-1 (P = 0.010) and sST2 (P = 0.032) levels. Neurolupus was associated with higher IL-1Ra (P = 0.038) and LN with lower IL-1Ra (P = 0.025) and sVCAM-1 (P = 0.036) levels. Higher IL-1Ra (P = 0.012), IL-17 (P = 0.045), IL-18 (P = 0.003), and sVCAM-1 (P = 0.062) levels were observed in patients with CMR MInj compared with those without. On multivariable logistic regression, IL-1Ra predicted CMR inflammation and fibrosis/necrosis (P < 0.005) while anti-Ro/SSA [odds ratio (OR): 1.197; P = 0.035] and the SLE damage index (OR: 4.064; P = 0.011) predicted fibrosis/necrosis.Conclusion: This is a novel description of associations between cytokines and SLE MInj. IL-18 and IL-1Ra were significantly higher in patients with MInj. IL-1Ra independently predicted different stages of CMR MInj. Exploration of the role of these cytokines in the pathogenesis of SLE MInj may promote targeted therapies for LM.

21 September 2022 in The Lancet Rheumatology
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DDDzifa Dey
Dzifa Dey
FPFarhanah Paruk
Farhanah Paruk
GMGirish M Mody
Girish M Mody
AKAsgar A Kalla
Asgar A Kalla
AAAdewale O. Adebajo
Adewale O. Adebajo
IHIhsane Hmamouchi
Ihsane Hmamouchi

1 December 2020 in Lupus
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Journal Article
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RTRiette du Toit
Riette du Toit
PHPhillip G Herbst
Phillip G Herbst
CAChristelle Ackerman
Christelle Ackerman
APAlfonso Jk Pecoraro
Alfonso Jk Pecoraro
DCDirk Claassen
Dirk Claassen
ADAnton F Doubell
Anton F Doubell
Objectives: To determine the outcome of subclinical lupus myocarditis (LM) over twelve months with regards to: mortality; incidence of clinical LM and change in imaging parameters (echocardiography and cardiac magnetic resonance [CMR]). To evaluate the impact of immunosuppression on CMR evidence of myocardial tissue injury. Methods: SLE patients with and without CMR evidence of myocardial injury (as per 2009 Lake Louise criteria [LLC]) were included. Analysis at baseline and follow-up included: clinical evaluation, laboratory and imaging analyses (echocardiography and CMR). Clinical LM was defined as clinical features of LM supported by echocardiographic and/or biochemical evidence of myocardial dysfunction. Subclinical LM was defined as CMR myocardial injury without clinical LM. Results: Forty-nine SLE patients were included with follow-up analyses (after 12 months) available in 36 patients. Twenty-five patients (51%) received intensified immunosuppressive therapy during follow-up for indications related to SLE. Disease activity (SLEDAI-2K) improved (p < 0.001) from 13 (median;IQR:9–20) to 7 (3–11). One patient without initial CMR evidence of myocardial injury developed clinical LM. Mortality (n = 10) and SLE clinical features were similar between patients with and without initial CMR myocardial injury. Echocardiographic left ventricular ejection fraction (LVEF) (p = 0.014), right ventricular function (p = 0.001) and wall motion abnormalities (p = 0.056) improved significantly but not strain analyses nor the left LV internal diameter index. CMR mass index (p = 0.011) and LVEF (p < 0.001) improved with follow-up but not parameters identifying myocardial tissue injury (LLC). A trend towards a reduction in the presence of CMR criteria was counterbalanced by persistence (n = 7) /development of new criteria (n = 11) in patients. Change in CMR mass index correlated with change in T2-weighted signal (myocardial oedema) (r = 386;p = 0.024). Intensified immunosuppressive therapy had no significant effect on CMR parameters. Conclusion: CMR evidence of subclinical LM persisted despite improved SLEDAI-2K, serological markers, cardiac function and CMR mass index. Subclinical LM did not progress to clinical LM and had no significant prognostic implications over 12 months. Immunosuppressive therapy did not have any significant effect on the presence of CMR evidence of myocardial tissue injury. Improvement in CMR mass index correlated with reduction in myocardial oedema and may be used to monitor SLE myocardial injury.