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ABSTRACT: The revised shared epitope (SE) concept in rheumatoid arthritis (RA) is based on the presence (S) or absence (X) of the SE RAA amino acid motif at positions 72 to 74 of the third hypervariable region of the various human leucocyte antigen (HLA)-DRB1 alleles. The purpose of this study was to investigate SE subtypes on the basis of the American College of Rheumatology 1987 revised criteria for the classification of RA in a cohort of South African RA patients (n = 143) and their association with clinical and circulating biomarkers of disease activity (autoantibodies, acute phase reactants and cytokines).
Genomic DNA was analysed using high-resolution recombinant sequence-specific oligonucleotide PCR typing of the HLA-DRB1 allele. Subtypes of the SE were classified according to the amino acids at positions 72 to 74 for the RAA sequence, and further sub-divided according to the amino acids at positions 70 and 71, which either contribute to (S2, S3P), or negate (S1, S3D) RA susceptibility. Disease activity was assessed on the basis of (1) Disease Activity Score in 28 joints using C-reactive protein (CRP), (2) rheumatoid factor (RF), (3) CRP and (4) serum amyloid A by nephelometry, anticyclic citrullinated peptide antibodies (aCCP) by an immunofluorometric procedure, and cytokines by multiplex bead array technology.
Of the 143 RA patients, 81 (57%) were homozygous (SS) and 50 (35%) were heterozygous (SX) for the SE alleles with significant overexpression of S2 and S3P (respective odds ratios (ORs) 5.3 and 5.8; P < 0.0001), and 12 (8%) were classified as no SE allele (XX). Both the SS and SX groups showed a strong association with aCCP positivity (OR = 10.2 and P = 0.0010, OR = 9.2 and P = 0.0028, respectively) relative to the XX group. Clinical scores and concentrations of the other biomarkers of disease activity (RF, CRP and T helper cell type 1 (Th1), Th2, macrophage and fibroblast cytokines) were also generally higher in the SS group than in the SX and XX groups.
RA susceptibility alleles investigated according to revised criteria for the classification of RA were significantly increased in South African RA patients and strongly associated with aCCP in particular as well as with circulating cytokines and disease severity.
Arthritis research & therapy 10/2011; 13(5):R160. · 4.27 Impact Factor
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ABSTRACT: To establish the diagnostic utility of the anti-cyclic-citrullinated peptide antibody (aCCP) test in Black South Africans with early rheumatoid arthritis (RA). A cross-sectional study comparing the rheumatoid factor (RF) and aCCP status in RA patients and a control group consisting of healthy subjects, and patients with systemic lupus erythematosus (SLE) and scleroderma. The sensitivity, specificity, positive (PPV) and negative predictive values of the aCCP test alone were 82.5%, 84.9%, 87.6% and 79% versus 81.7%, 90.7%, 92.5% and 78% for RF alone. The best specificity (95.3) and PPV (95.8%) was observed when both aCCP and RF tests were positive. Patients with erosive disease had a significantly higher mean RF titre compared with those with non-erosive disease (p = 0.007). There was a trend towards an association of smoking (OR = 4.1, 95% CI = 0.9-18.6) and functional disability (p = 0.07) with RF-positive status. No similar clinical associations were observed with aCCP. Almost a third of SLE patients were aCCP positive. Despite the best specificity and PPV observed when both the aCCP and RF tests were positive, our findings suggest that testing for aCCP is only cost-effective in the RF-negative patient in whom there is a strong clinical suspicion of RA.
Clinical Rheumatology 06/2010; 29(6):615-8. · 2.00 Impact Factor
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ABSTRACT: Our objective was to analyse the relationship between circulating cytokines, autoantibodies, acute phase reactants, and disease activity in DMARDs-naïve rheumatoid arthritis (RA) patients (n = 140). All cytokines were significantly higher in the RA cohort than in healthy controls. Moderate-to-strong positive intercorrelations were observed between Th1/Th2/macrophage/fibroblast-derived cytokines. RF correlated significantly with IL-1β, IL-2, IL-4, IL-10, IL-12, G-CSF, GM-CSF, IFN-γ, and TNF (P < .0001), and aCCP and aMCV with IL-1β, IL-2, IL-4, and IL-10 (P < .0002), while IL-6 correlated best with the acute phase reactants, CRP, and SAA (P < .0001). In patients with a DAS28 score of ≥5.1, IFN-γ, IL-1β, IL-1Ra, TNF, GM-CSF, and VEGF were significantly correlated (P < .04-.001) with high disease activity (HDA). Circulating cytokines in RA reflect a multifaceted increase in immune reactivity encompassing Th1 and Th2 cells, monocytes/macrophages, and synovial fibroblasts, underscored by strong correlations between these cytokines, as well as their relationships with RF, aCCP, and aMCV, with some cytokines showing promise as biomarkers of HDA.
Mediators of Inflammation 01/2010; 2010:158514. · 3.26 Impact Factor
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ABSTRACT: The aim of this study was to compare clinical, microbiological, enzymatic, and host immune response variables between subjects hospitalized with facial cellulitis, with Ludwig's angina (LA) and without Ludwig's angina (WOLA).
Microbiological and enzymatic tests on pus, and hematological and immunological assessments on blood samples of 15 patients with LA and 42 patients with WOLA were performed. Laboratory findings of both groups were compared using the Student t test. Multiple logistic regression analysis was performed and significant differences identified by univariate analysis.
Patients with LA demonstrated increased levels of white blood cell counts, urea, and CRP levels, and decreased levels of CIC compared with patients WOLA. However, only CRP and urea were found to be significantly raised in the LA group. A greater population of Staphylococcus aureus and black-pigmented bacteroides were isolated from patients with LA.
Elevated levels of CRP and urea could indicate the severity of infection in patients with LA. This could be because of the highly virulent and fast-spreading organisms, S. aureus and black-pigmented bacteroides, which may be a factor indicative of LA.
Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 11/2009; 108(5):667-72. · 1.50 Impact Factor
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ABSTRACT: Mycobacterium tuberculosis (M.tb) infects 8 million and kills 2.2 million people each year worldwide. M.tb modulates the immune response of the infected individual. Empirically, suppressor carbohydrates (SC) produced by CD8+ T cells in response to M.tb were found to induce a T helper 2 response rather than a protective T helper 1 response in human mononuclear (MN) cells. This study (1) identifies the genes that modulate the T helper response, (2) describes their function, and (3) postulates a detailed model for the M.tb infection mechanism. MN cells from five healthy donors were pulsed with SC and gene expression profiles of 18,861 genes were assessed in a micro-array experiment. Twenty-eight genes were found to be increased and 60 genes were decreased (FDR=1%, fold change>1.4) in response to SC. MIP3 alpha and platelet factor 4 (v1) are both significantly enriched (p< or =0.001) in the GO category "chemokine activity". Repressed genes were significantly (p< or =0.001) over-represented in the GO terms "response to pathogenic bacteria", "inflammatory response", "coagulation" and "apoptosis". Indeed, SC significantly reduced numbers of Annexin V/CD4+ cells, while inducing hypoproliferation in CD4+ and non-adherent lymphocytes. This may indicate that M.tb renders a portion of the CD4+ T cell population unresponsive. Furthermore, validating QRT-PCR analysis suggests that monocytes provide an immuno-modulatory signal to CD4+ T cells in M.tb infection. These observations will allow development of new therapeutic interventions to restore the desired T helper 1 response.
Molecular Immunology 03/2008; 45(6):1573-86. · 2.90 Impact Factor
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ABSTRACT: Three adaptive hypotheses have been proposed to explain the link between the human leucocyte antigen (hla) genes, health measures and facial attractiveness: inbreeding avoidance, heterozygote advantage and frequency-dependent selection. This paper reports findings that support a new hypothesis relating HLA to health. We suggest a new method to quantify the level of heterozygosity. HLA heterozygosity did not significantly predict health measures in women, but allele frequency did. Women with more common HLA alleles reported fewer cold and flu bouts per year, fewer illnesses in the previous year and rated themselves healthier than women with rare alleles. To our knowledge, this is the first study to show a positive correlation between HLA allele frequency and general health measures. We propose that certain common HLA alleles confer resistance to prevalent pathogens. Nevertheless, neither HLA heterozygosity nor allele frequency significantly predicted how healthy or attractive men rated the female volunteers. Three non-mutually exclusive explanations are put forward to explain this finding.
PLoS ONE 02/2007; 2(7):e640. · 4.09 Impact Factor
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South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 09/2006; 96(8):663-4. · 2.04 Impact Factor
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ABSTRACT: During the early 1900s, African populations in South Africa were subject to very widespread infections which especially affected the young. This resulted in high mortality rates and a low life expectancy of 20-25 years. By the mid-century, mortality rates from infections had decreased considerably. Moreover, the occurrences of non-communicable diseases, even in urban areas, remained very low. In the 1970s, the proportion of Africans aged 50 or over that reached 70 years was 38.5%, higher than that in the juxtaposed white population, which was 35.5%. And by 1985, the life expectancy of Africans reached 61 years for males and 63 years for females, probably the highest in sub-Saharan African populations. Since then, however, the African continent has been devastated by the AIDS epidemic. In 2001, HIV was responsible for the death of a third of the African population in South Africa, but even higher proportions prevailed in Botswana and in Tanzania. The calamitous advent of the HIV infection has caused major falls in life expectancy, in the case of Africans in South Africa reducing this to just 43 years. With little hope of meaningful changes occurring in sexual habits or of an early vaccine becoming available, the infection's high morbidity/mortality burden is likely to continue.
The Journal of the Royal Society for the Promotion of Health 08/2005; 125(4):168-71. · 0.41 Impact Factor
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South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 08/2005; 95(7):482. · 2.04 Impact Factor
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The Journal of the Royal Society for the Promotion of Health 08/2004; 124(4):160-1. · 0.41 Impact Factor
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South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 03/2004; 94(2):102-3. · 2.04 Impact Factor
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South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 03/2003; 93(2):125-6. · 2.04 Impact Factor
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ABSTRACT: Although abnormalities of the immune system have been described in depression, information on serological alteration in acutely manic patients has been scarce. The present study undertook to investigate the levels of C-reactive proteins, circulating immune complexes, total immunoglobulins and immunoglobulin subclasses, complement proteins C3, C4, C6 and Factor B in the sera of 45 patients suffering from an acute manic episode. The findings were compared with assessments on the sera of 45 controls. The results demonstrate a number of significant differences between patients and controls. Whilst levels of immunoglobulin D were significantly lower, the levels of total immunoglobulin and immunoglobulin G1, complement proteins C3, C6 and Factor B were raised in the patient group when compared with the controls. Our results suggest a relationship between acute mania and immunological parameters associated with acute phase responses.
Human Psychopharmacology Clinical and Experimental 07/2002; 17(4):175-9. · 2.48 Impact Factor
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Bulletin of the World Health Organisation 02/2002; 80(4):333. · 4.64 Impact Factor
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ABSTRACT: In heart failure, increased circulating white cell tumour necrosis factor-alpha production could be attributed to elevated plasma endotoxin concentrations or an increase in white cell sensitivity to endotoxin.
To ascertain whether, in patients with IDC, circulating white cell TNF-alpha production is also mediated through endotoxin-independent mechanisms.
Whole blood production of TNF-alpha, both with and without the presence of an endotoxin stimulus, was evaluated in 89 controls and in 60 patients with IDC in New York Heart Association functional class I, II or III heart failure and without evidence of oedema, reduced peripheral perfusion or elevated plasma endotoxin concentrations. Circulating concentrations of selected pro and anti-inflammatory factors were also measured.
In patients compared to controls, IgG (p < 0.01) (IgG1 and IgG3), but not IgM concentrations were elevated, and plasma TNF-alpha and TGF-beta concentrations were raised (p < 0.001, p < 0.02 respectively). In addition, endotoxin-free cultured whole blood TNF-alpha production (p < 0.0005) was increased. Against a role for endotoxin-mediated pre-activation of white cells in patients, the sensitivity of white cells to endotoxin, as determined from the excitatory endotoxin concentration producing 50% maximal TNF-alpha production was unchanged. Moreover, in favour of non-endotoxin-mediated white cell activation, the calcineurin inhibitor, cyclosporin-A, which did not alter endotoxin-induced TNF-alpha production, decreased TNF-alpha produced by unstimulated cultured cells in patients to values not significantly greater than those in controls.
We concluded that circulating white cell cytokine over-production can occur through both endotoxin- dependent and -independent mechanisms in IDC.
Cardiovascular journal of South Africa: official journal for Southern Africa Cardiac Society [and] South African Society of Cardiac Practitioners 16(5):260-5.
