Anis Riahi

Association of HLA-DR/DQ polymorphisms with Guillain–Barré syndrome in Tunisian patients

UNLABELLED Human leukocyte antigen (HLA) alleles have been implicated in many autoimmune diseases. The aim of this study is to assess whether HLA-DR/DQ alleles confer susceptibility to Guillain-Barré syndrome (GBS) in a Tunisian population. METHODS The HLA-DR/DQ genotyping was performed using polymerase chain reaction sequence-specific primers (PCR-SSP) in 38 patients with GBS and 100 healthy Tunisian control subjects. RESULTS GBS in Tunisian patients was found to be associated with the following alleles with these relative patient versus control frequencies (pc denotes Bonferroni corrected probability values): DRB1*13 (23.68% vs. 9.0%; pc=0.01), followed by DRB1*14 (22.36% vs.5.5%; pc<10(-3)). Two haplotypes, DRB1*14/DQB1*05 and DRB1*13/DQB1*03, were found to be associated with susceptibility to GBS. However DRB1*07/DQB1*02 and DRB1*03/DQB1*02 haplotypes were more frequently observed in controls than in patients (11.5% vs.7.9%; pc=0.007 and 23% vs. 5.26%; pc<10(-3) respectively). These haplotypes seem to confer protection against the disease. CONCLUSION Our data demonstrated a new GBS predisposition associated with HLA-DRB1*14 and DRB1*13. Theses alleles could be predisposing genetic factors for GBS in the Tunisian population.

Clinical features and disability progression in multiple sclerosis in Tunisia: Do we really have a more aggressive disease course?

BACKGROUND Few epidemiological data are available on multiple sclerosis (MS) patients in North Africa (NA). Studies of immigrants from NA showed a more aggressive course compared to European patients. OBJECTIVE The aim of this study is to describe clinical and long term course characteristics of MS in Tunisia and to compare it to European cohorts. METHOD A total of 437 MS patients from three hospital based cohorts in Tunisia and having prospective follow up between 2010 and 2012 were analyzed. We considered as endpoints the time to reach EDSS scores of 3, 4 and 6 in the different clinical forms of MS and the beginning of a secondary progressive (SP) phase. RESULTS Sex ratio was 2.34. Mean age of onset was 30.3 years. The course was relapsing-remitting (RR) in 91% of patients and primary progressive (PP) in 9%. The most frequent isolated onset symptoms were respectively motor (28%), optic neuritis (20%) and sensory (16%) dysfunction. Median time to SP onset was 19.1 years. Median times from onset of multiple sclerosis to assignment of a score of 3, 4 and 6 were 8, 10.7 and 15 years respectively. Benign form of MS represented 31.5%. Median interval from the onset of the disease to EDSS score of 3, 4 and 6 was shorter in PP-MS than in RR-MS. However, there was no difference between these two groups for the median time from the assignment of EDSS 4 to the assignment EDSS 6. CONCLUSIONS Our study shows that Tunisian MS patients have a quite similar clinical feature to European patients. Still, larger MS multicenter cohort studies in NA with longer follow-up duration could clearly respond to the issue.

Association of HLA-DR/DQ polymorphism with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in Tunisian patients.

BACKGROUND AND OBJECTIVE Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated disorder of the peripheral nervous system (PNS). The aim of this study was to investigate associations between HLA-DR/DQ alleles and CIDP in Tunisian patients. PATIENTS AND METHODS HLA DR/DQ genotyping was performed using polymerase chain reaction sequence-specific primers (PCR-SSP) with 36 CIDP patients and 100 healthy individuals serving as the control group. RESULTS CIDP in Tunisian patients was found to be associated with the HLA-DRB1*13 allele (pc=0.03) (where pc denotes the Bonferroni corrected probability value). Moreover, the two haplotypes, DRB1*13/DQB1*06 (22.22% of patients vs. 8.5% of controls, pc=0.017) and DRB1*07/DQB1*03 (13.88% of patients vs. 3% of controls, pc=0.005), were found to confer a susceptibility to CIDP. CONCLUSION To our knowledge, this is the first study performed to analyze the association of HLA-DRB1/DQB1 alleles on CIDP susceptibility in a Tunisian population.

Pascal white noise calculus

In this paper white noise analysis with respect to the Lévy process with negative binomial distributed marginals is investigated. An appropriate space of distributions, ℰ ′, is used to describe the structure of the Hilbert space of quadratic integrable functionals with respect to the Pascal white noise measure ΛNB. The constructed decomposition is used to define a nuclear triple of test and generalized functions, where θ is a Young function satisfying some suitable conditions. By using the 𝒮-transform and the symbol transform σNB, a general characterization theorems are proven for Pascal white noise distributions, white noise test functions and white noise operators in terms of analytical functions with growth condition of exponential type. As application, some quantum stochastic differential equations are solved with special emphasis on Wick calculus.

UNITARY REPRESENTATIONS OF THE WITT AND sl(2, ℝ)-ALGEBRAS THROUGH RENORMALIZED POWERS OF THE QUANTUM PASCAL WHITE NOISE

By using an appropriate space of distributions, , we derive the chaos decomposition property of the Hilbert space of quadratic integrable functionals with respect to the Pascal white noise measure ΛNB. The constructed decomposition is used to define a nuclear triple of test and generalized functions, where θ is a Young function satisfying some suitable conditions. A general characterization theorems are proven for the Pascal white noise distributions, white noise test functions and white noise operators in terms of analytical functions with growth condition of exponential type. By using appropriate renormalization procedure, we obtain the representation of the square of white noise obtained by Accardi–Franz–Skeide in Ref. 5. Finally, we investigate the main aim of this paper which is to give unitary equivalent representations of the Witt algebra in the basis of Pascal white noise theory.

The quantum decomposition of random variables without moments

The quantum decomposition of a classical random variable is one of the deep results of quantum probability: it shows that any classical random variable or stochastic process has a built-in non-commutative structure which is intrinsic and canonical, and not artificially put by hands. Up to now the technique to deduce the quantum decomposition has been based on the theory of interacting Fock spaces and on Jacobis tri-diagonal relation for orthogonal polynomials. Therefore it requires the existence of moments of any order and cannot be applied to random variables without this property. The problem to find an analogue of the quantum decomposition for random variables without finite moments of any order remained open for about fifteen years and nobody had any idea of how such a decomposition could look like. In the present paper we prove that any infinitely divisible random variable has a quantum decomposition canonically associated to its Levy–Khintchin triple. The analytical formulation of this result is based on Kolmogorov representation of these triples in terms of 1–cocycles (helices) in Hilbert spaces and on the Araki–Woods–Parthasarathy–Schmidt characterization of these representation in terms of Fock spaces. It distinguishes three classes of random variables: (i) with finite second moment; (ii) with finite first moment only; (iii) without any moment. The third class involves a new type of renormalization based on the associated Levy–Khinchin function.

Recurrent status epilepticus in posterior reversible encephalopathy syndrome as initial feature of pediatric lupus: A newly diagnosed case and literature review

INTRODUCTION Posterior reversible encephalopathy syndrome (PRES) is a recently described clinico-neuroradiological syndrome with several predisposing conditions. Systemic lupus erythematosus (SLE), beginning in 15-20% in childhood, is considered as a potential underlying etiology of PRES. In children, status epilepticus (SE) rarely complicates PRES, and exceptionally occurs in SLE. METHODS We report on an illustrative case of PRES complicating pediatric lupus revealed by recurrent SE, and we further review through a Pubmed search the previously reported cases of pediatric SLE, PRES and SE. RESULTS We describe the case of a 12-year old girl who presented with recurrent status epilepticus associated to high blood pressure and renal involvement. Brain imaging showed classical aspects of PRES. Immunological tests including antinuclear, anti-DNA, and anticardiolipin antibodies were positive. The diagnosis of SLE was established. The Pubmed search identified a total number of 9 children with SE in SLE, and 26 with PRES, including our patient. CONCLUSIONS We discussed the clinical and paraclinical features of PRES in SLE with epilepsy, their underlying pathophysiological aspects, and their management challenges. PRES should be considered in initial recurrent SE in children, justifying a battery of tests comprising immunological testing. Anticardiolipin antibodies seem to play a crucial role in epilepsy, PRES and renal involvement in pediatric SLE. Further studies are needed to clarify whether PRES should be considered one of the neuropsychiatric manifestations of SLE or a consequence of active disease in other organ systems or its treatment.

Les manifestations neurologiques de la sarcoïdose : étude de 18 cas

INTRODUCTION Sarcoidosis is a multisystemic granulomatous disease of unknown aetiology. Neurologic manifestations are found in 5 to 10% of cases. PATIENTS AND METHODS We conducted a retrospective study over 6-year period including 18 patients diagnosed with neurosarcoidosis in the Neurologic department of the Military Hospital of Instruction of Tunis. Clinical, radiological, therapeutic features and outcome were studied. RESULTS The mean age was 43.44 years. Neurologic signs were the first symptom in 10 cases. Peripheral nervous system impairment was often found. Meningitis was noted in 8 cases. Biological tests are not contributive for the diagnosis. The brain magnetic resonance imaging was pathologic in 10 cases. Corticosteroids were administrated in the majority of cases. Eight patients did not show any sign of improvement. Ten cases improved with treatment. DISCUSSION AND CONCLUSION Diagnosis of neurosarcoidosis is difficult because of its clinical and radiological polymorphism. It is based on a clinical history suggestive of neurosarcoidosis, laboratory, imaging and histological studies.

Nuclear Realization of Virasoro–Zamolodchikov-w∞ ⋆-Lie Algebras Through the Renormalized Higher Powers of Quantum Meixner White Noise

By using an appropriate one-mode type interacting Fock spaces, , introduced in [1], we define a nuclear triple of test and generalized functions, with θ being a suitable Young function. Moreover, we prove general characterization theorems for the fundamental nuclear spaces. For the applications, we introduce new renormalized products for the generators of the renormalized higher powers of white noise ⋆-Lie algebra and the Virasoro-Zamolodchikov-w∞ ⋆-Lie algebra. Then we show that these new renormalized products lead to nuclear realizations of these Lie algebras in terms of quantum Meixner white noise operators.

The Plasminogen Activator Inhibitor 1 4G/5G Polymorphism and the Risk of Alzheimer's Disease.

Objective: The aim of this study was to determine whether plasminogen activator inhibitor 1 (PAI-1) is associated with the risk of Alzheimer’s disease (AD) in Tunisian patients. Design and Methods: We analyzed the genotype and allele frequency distribution of the PAI-1 polymorphism in 60 Tunisian patients with AD and 120 healthy controls. Results: The results show a significantly increased risk of AD in carriers of the 4G/4G and 4G/5G genotypes versus the wild-type 5G/5G genotype (4G/4G: 28.33% in patients vs 10.0% in controls; P < 10−3; OR = 8.78; 4G/5G: 55.0% in patients vs 38.33% in controls; OR = 4.45; P < 10−3). The 4G allele was also more frequently found in patients compared with controls; P < 10−3; OR = 3.07. For all participants and by gender, homozygotic carriers (4G/4G) were at an increased risk of AD over heterozygotes and women were at an increased risk over their male genotype counterparts. The odds ratio for AD among 4G/4G carriers for any group was approximately twice that of heterozygotes in the same group. Women homozygotes ranked highest for AD risk (OR = 20.8) and, in fact, women heterozygotes (OR = 9.03) ranked higher for risk than male homozygotes (OR = 6.12). Conclusion: These preliminary exploratory results should be confirmed in a larger study.