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K Ayed

Publications and source records attributed to K Ayed.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Anti-DNA antibodies: structure and pathogenic role].

Anti DNA antibodies are generally classified into two major groups: Anti ds DNA (anti double .. stranded DNA) antibody and anti ss-DNA (anti single-stranded DNA) antibody. Anti-ds DNA antibodies are highly specific to systemic lupus erythematosus (SLE) and are probably involved in the pathogenesis of lupus nephritis. There are numerous serological tests for detecting anti-ds DNA. The detection of anti-ds DNA antibodies in the circulation of patients is one of the major criteria for the diagnosis of SLE; moreover, exacerbation of the disease are proceeded by increasing anti-DNA levels and the development of lupus nephritis, one of the most serious complications of the disease, strongly correlates with the presence of high avidity anti-DNA. It was reported that even normal individuals express anti-ds DNA. However, anti ds DNA found in healthy individuals is usually of the immunoglobulin M (IgM) isotype and shows a low affinity to ds-DNA. These natural antibodies are characterized by a wide cross-reactivity and are usually encoded by gene segments in the germ line configuration. In contrast, the ds-DNA antibodies involved influenced by various findings supporting the proposition that anti-ds DNA is involved in the pathogenesis of SLE, an enormous amount of scientific investigation has failed to reveal the exact mechanism through which this occurs.

Animals↗
PubMed1999

Immunoblot and immunoelectronmicroscopic analysis of endemic Tunisian pemphigus.

Tunisian pemphigus is a newly described form of endemic pemphigus whose clinical, histological and epidemiological characteristics have recently been detailed. The objective of this study was to analyse the binding properties of autoantibodies present in sera from patients with endemic Tunisian pemphigus using immunoblotting and indirect immunoelectron microscopy (IEM). Thirty patients with pemphigus foliaceus (PF) and six with pemphigus vulgaris (PV) seen in the dermatology department of Tunis Hospital between 1992 and 1994 were selected for this study. Seven of 30 (23%) and six of 12 (50%) PF sera tested bound to the 160 kDa band of desmoglein 1 when tested on bovine tongue and human epidermal extracts, respectively. Two of six and two of three PV sera tested bound to the 130 kDa desmoglein 3 in these two extracts. Immunoblot and indirect IEM showed that 24 of 30 (80%) PF sera contained IgG1, IgG3 or IgG4 antibodies that bound to a 185-kDa polypeptide localized on the desmosomal plaque. This immunological analysis showed that most endemic Tunisian pemphigus sera correspond to PF sera and are characterized by a high frequency of autoantibodies directed against a recently identified 185-kDa antigen of the desmosomal plaque.

Adult↗
PubMed1998

[Detection of hepatitis C virus in the general population of Tunisia].

We searched for antibodies to hepatitis C in a sample of 3079 Tunisians in the suburban area of Tunis. 30 people were positive by ELISA and 22 were confirmed by immunoblotting. This result represents a prevalence of 0.71% which is close to the values reported in European countries of the Mediterranean area.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

[Interference of factor VIII excess on the detection of lupus anticoagulants by the activated partial thromboplastin time].

Antiphospholipids antibodies (AAP) were investigated in plasma of 62 patients with systemic lupus erythematosus, and studied for the possible interference of the excess in factor VIIIc-Von Willebrand factor (VWF-VIIIc) complex in the detection of lupus anticoagulants (LA) by the activated partial thromboplastin time (APTT). We used four commercial reagents and noted that each one exhibited a different level of sensitivity of LA; the most sensitive one allowed the detection of 16 LA positive plasmas while the less sensitive reagent detected only 6 positives. The Elisa test for IgG and IgM AAP detection was positive in 25 out of 62 plasmas (40%). Comparison of the Von Willebrand factor antigen level and the APTT values showed a significant negative corrélation with 2 reagents (r = 0.369, p < 0.01 and r = 0.272, p < 0.05 respectively) that were also the less sensitive to LA. The interference of an excess in VWF-VIIIc complex was further studied by the addition of purified factor VIII in 3 LA positive plasmas. Our results suggests that an excess of factor VIIIc could lead to false negative LA, using certain APTT reagents. We conclude that a more accurate LA detection require: sensitive reagents, a pool of normal plasmas selected with normal factor VIII level, as well as repeated testing of blood sampling withdrawn away of an inflammatory process to avoid false negative LA detection.

Adolescent↗
PubMed1996

Endothelin-1 expression in serum and bronchoalveolar lavage from patients with active Behçet's disease.

In view of the pulmonary manifestations in Behçet's disease (BD), we investigated the production of endothelin-1 (ET-1) by the respiratory tract in active BD. A group of 10 patients with active BD with pulmonary manifestations and 10 control subjects were studied. Immunoreactive ET-1 was measured in BAL and in serum by RIA. All the BD patients exhibited higher BAL ET-1 levels than controls. ET-1 expression may contribute to the functional and morphological abnormalities of the vasculature associate with BD.

Adult↗
PubMed1996

[Value of the search for anticardiolipin antibodies during the course of systemic lupus erythematosus].

The anticardiolipin antibodies (aCL) are acquired inhibiting antibodies of the coagulation process. They interfere with the anionic phospholipids of the cellular membranous. These are frequently associated to the autoimmune diseases, especially the systemic lupus erythematosus (SLE), they expose the patient to thrombotic complications. In order to define the possible and prognostic predictive value of these aCL, a sequential research of these antibodies was performed on 12 patients suffering from SLE since 2 to 11 years. An average of one sample per year was drawn, either during an attack or in a routine control check. The detection of these IgG aCL did not appear to be related with be course of the disease. In fact, 3 of our patients, ill since respectively 2, 7 and 11 years, never showed any aCL. These aCL were positive during an attack in 80% of the cases. This positivity was associated to vascular thrombosis (2 cases), and cutaneous vascularity (6 cases) and, in one case, the presence of aCL was linked to inutero fetal death due to retruplacentary hematoma. This study confirms the association between aCL and thrombosis during systemic lupus erythematosus.

Adolescent↗
PubMed1994

[Iga linear bullous dermatosis in children. A series of 12 Tunisian patients].

BACKGROUND: Linear IgA bullous dermatosis (LABD) of childhood is one of the chronic, non-hereditary blistering diseases of childhood in which clinical, histologic and therapeutic findings are similar to those associated with bullous pemphigoid (BP) and dermatitis herpetiformis (DH). LABD, however, can be distinguished from BP of DH by direct immunofluorescence (IF) demonstration of linear IgA deposits along the basement membrane zone (BMZ). RESULTS: During the period 1984-1993, 12 children with LABD were studied. Their ages ranged from 2 years to 15 years with a mean of 8.5 years. There were 7 males and 5 females. All children had a generalized eruption consisting of large tense blisters arising on normal skin. The blisters were more profuse on the lower trunk, pelvic region and limbs. Face and scalp were also affected. Occasionally, annular blister formation producing a "rosette" or "cluster of jewels" was found. Pruritus was frequent. Histological features of BP and DH were seen. Direct IF showed linear deposits of IgA at the BMZ in all cases. IgM, IgG, and complement were also seen in 8 cases. Four patients showed IgA BMZ antibodies by indirect IF. There were no symptoms of malabsorption and 3 patients had a mild bowel lesions. HLA studies showed the B8DR3 antigen in 7 of the 10 patients studied. Nine patients were treated with dapsone associated in 3 patients with prednisone. Three patients were controlled on oxacillin. CONCLUSION: LABD of childhood is a definite clinical entity. It is the most frequent chronic, non hereditary bullous disease of childhood in Tunisia. It is characterized by a self limiting blistering eruption which resembles BP or DH histologically and has a characteristic linear deposits of IgA at the BMZ of the skin. The treatment consisted on dapsone therapy, but 3 patients in our study were well controlled on oxacillin.

Adolescent↗
PubMed1994

Phenotype and functional profile of T cells expressing gamma delta receptor from patients with active Behçet's disease.

OBJECTIVE: Our aim was to investigate the TCR gamma delta+ subset in Behçet's disease (BD) inflammatory sites, which better reflects changes associated with the pathologic process than peripheral blood. METHODS: Forty-five patients with active BD, 10 patients with recurrent aphthous ulcers, 12 patients with rheumatoid arthritis, 5 patients with noninflammatory neurologic diseases and 15 healthy individuals were studied. Three monoclonal antibodies TCR delta 1, BB3, and A13 were used to assess the percentage of TCR gamma delta+ in peripheral blood mononuclear cells (PBMC), in bronchoalveolar lavage and cerebrospinal fluid (CSF). CD11a/CD18 was used to study adhesion molecules. TCR gamma delta+ cells isolated by immunomagnetic separation were tested for cytolytic activity against K562 target cells after interleukin 2 stimulation. RESULTS: The PBMC TCR gamma delta BB3+ subset was significantly increased in BD. In BD inflammatory sites, TCR gamma delta+ cells were also present, composed mainly of A13+ cells from these sites also expressed CD11a marker. TCR gamma delta+ cells from inflammatory sites displayed a higher cytotoxic activity than controls, mediated by the A13+ subset. CONCLUSION: The accumulation of cytotoxic TCR gamma delta+ cells at the sites of inflammation suggests their involvement in the local injury process.

Adult↗
PubMed1994

Characteristics of polyreactive and monospecific IgG anti-laminin autoantibodies in the rat mercury model.

Brown-Norway (BN) rats injected with HgCl2 produce anti-laminin antibodies responsible for an autoimmune glomerulonephritis. The properties of three IgG1 monoclonal antibodies (mAb) previously obtained in this model, and of immunoglobulins eluted from kidneys of diseased rats, were compared in the present study. Two mAb (Hg15 and Hg16) recognized laminin only, while the third one (Hg17) was polyreactive, as were some of the kidney-eluted immunoglobulins; they reacted with laminin and with several other antigens including 2,4,6-trinitrophenyl (TNP). The Hg17 mAb and kidney-eluted polyreactive antibodies were affinity purified using a TNP-bovine serum albumin (BSA) column; their affinity for TNP was high (2 x 10(-8)M, and 1 x 10(-8)M, respectively) but less than that of a TNP-specific (LO-DNP-2) mAb (2 x 10(-11) M). The Hg17 mAb and kidney-eluted antibodies reacted more effectively with TNP28-BSA than with TNP8.5-BSA, while the TNP-specific mAb reacted equally well with both conjugates. The Hg17 mAb was the most cationic (pI: 7) of the anti-laminin mAb and this was even more evident when F(ab')2 fragments were studied (pI: 8.2). The polyreactive kidney-eluted immunoglobulins that bound TNP were also more cationic (pI: 7.4-9.3) than the fraction that did not recognize TNP (pI: 5.8-8.6). The anti-laminin mAb bound in vivo to the glomerular basement membrane, but only the Hg17 mAb could be eluted with DNP alone. This study shows that polyreactive anti-laminin antibodies are produced during this autoimmune disease, and indicates that they may have pathogenic potential.

Animals↗
PubMed1993

[Lupus in children in Tunisia].

In this study, we have analyzed the clinical and serological features related to 16 Tunisian children in whom diagnosis of systemic lupus erythematosus was made before or at the age of 15. Renal involvement was found in 75% of cases and renal biopsies have mostly revealed severe histologic patterns. All of the patients who have been followed received corticosteroids and in some cases required additional cytotoxic drugs in order to control disease activity. Five children died in a context of a renal failure. This study of childhood lupus in Tunisia confirms that the clinical course of this disease in children is often aggressive.

Adolescent↗