Biomedical subjects

Salim Trad

Publications and source records attributed to Salim Trad.

5 recordsLinked to original sources

PubMed2006

The immune paradox of sarcoidosis and regulatory T cells.

Sarcoidosis is characterized by extensive local inflammation (granuloma, cytokine secretion) associated with anergy (poor response to antigens in vitro and in vivo). We postulated that this paradoxical situation would correspond to a disequilibrium between effector and regulatory T lymphocytes (T reg cells). We show that CD4+CD25(bright)FoxP3+ cells accumulate at the periphery of sarcoid granulomas, in bronchoalveolar lavage fluid, and in peripheral blood of patients with active disease. These cells exhibited powerful antiproliferative activity, yet did not completely inhibit TNF-alpha production. Sarcoidosis is therefore associated with a global T reg cell subset amplification whose activity would be insufficient to control local inflammation. At the same time, peripheral T reg cells exert powerful antiproliferative activity that may account for the state of anergy. Altogether, these findings advance our conceptual understanding of immune regulation in a way that resolves the immune paradox of sarcoidosis and permit us to envisage a profound clinical impact of T reg cell manipulation on immunity.

Adult↗

PubMed2006

Pulmonary arterial hypertension is a major mortality factor in diffuse systemic sclerosis, independent of interstitial lung disease.

OBJECTIVE: To determine whether pulmonary arterial hypertension (PAH) is a prognostic factor for mortality in diffuse cutaneous systemic sclerosis (dcSSc), independent of interstitial lung disease (ILD). METHODS: ILD was diagnosed by high-resolution computed tomography and PAH (pulmonary arterial systolic pressure [PASP] > or =45 mm Hg) by echocardiography. All patients with ILD underwent testing for total lung capacity (TLC), forced vital capacity (FVC), and diffusing capacity for carbon monoxide. RESULTS: Eighty-six patients with dcSSc (mean age at diagnosis 44.5 years) were followed up for a median of 72.5 months. ILD was found in 52 patients (60%) and PAH in 18 (21%). ILD was associated with PAH in 15 patients. Seventeen patients died (19.8%), 9 of whom had PAH (P = 0.001) and 10 of whom had ILD (P = 0.99). By multivariate analysis, age at SSc diagnosis and PAH were the only independent predictors of death (hazard ratio [HR] 1.057, 95% confidence interval [95% CI] 1.009-1.109, P = 0.020 and HR 4.09, 95% CI 1.47-11.5, P = 0.007, respectively). Mean TLC and mean FVC were similar in ILD patients with and those without PAH (P = 0.71 and P = 0.40, respectively). Among ILD patients, age at SSc diagnosis and PAH were again the sole predictors of death (HR 1.073, 95% CI 1.003-1.149, P = 0.042 and HR 5.07, 95% CI 1.09-23.8, P = 0.038, respectively). Twenty ILD patients received at least 6 monthly pulses of intravenous cyclophosphamide (CYC). In CYC-treated patients with PAH (n = 8), PASP increased significantly during the CYC regimen (mean +/- SD 55 +/- 14.5 mm Hg; P = 0.015 versus baseline), while TLC remained stable during the same period. CONCLUSION: These results indicate that, independent of ILD, PAH is a major prognostic factor for survival in dcSSc.

Adult↗

PubMed2005

Global natural regulatory T cell depletion in active systemic lupus erythematosus.

The immune defect that could account for the multisystemic involvement that characterizes systemic lupus erythematosus (SLE) remains unknown. We hypothesized that iterative disease flares correspond to a recurrent defect in the peripheral immune suppression exerted by naturally occurring T regulatory cells (Tregs). Surprisingly, Tregs isolated from lupus patients show the same phenotypic and functional characteristics as corresponding cells found in healthy controls. A decrease in the proportion of circulating Tregs among other CD4+ T cells is nevertheless evidenced in active patients when this group is compared with healthy controls (0.57 +/- 0.24%, n = 45 vs 1.29 +/- 0.38%, n = 82, p < 0.0001) or with inactive patients (1.22 +/- 0.67%, n = 62, p < 0.0001). In contrast, the proportion of Tregs in other systemic autoimmune diseases such as primary Sjögren syndrome and inflammatory myopathy does not significantly differ from controls' values (1.15 +/- 0.46%, n = 21, p = 0.09 and 1.16 +/- 0.44%, n = 16, p = 0.43, respectively). Lupus Tregs do not accumulate in either the lymph nodes or the diseased kidneys and are not killed by a circulating soluble factor, but demonstrate in vitro a heightened sensitivity to Fas-induced apoptosis. Finally, we show that the extent of Treg depletion correlates with the clinical severity of the flare. SLE flares are therefore associated with a global Treg depletion and not with a phenomenon of tissue redistribution. In summary, we suggest that the physiopathology of SLE could be tied to a defect in the homeostatic control of the Treg subpopulation.

Adolescent↗

PubMed2005

Nuclear bilateral Bell's palsy and ageusia associated with Mycoplasma pneumoniae pulmonary infection.

This case report describes a case of nuclear bilateral Bell's palsy and ageusia associated with Mycoplasma pneumoniae infection. Magnetic resonance imaging evidenced T2-weighted hyper-intense protuberantial lesions. Such topography leading to a nuclear palsy contrasts with previously reported infectious diplegia involving only peripheral facial nerves, and has not yet been described in the spectrum of M. pneumoniae post-infectious neurological manifestations.

Ageusia↗

PubMed2004

DNA macroarray for identification and typing of Staphylococcus aureus isolates.

A DNA macroarray containing 465 intragenic amplicons was designed to identify Staphylococcus aureus at the species level and to type S. aureus isolates. The genes selected included those encoding (i) S. aureus-specific proteins, (ii) staphylococcal and enterococcal proteins mediating antibiotic resistance and factors involved in their expression, (iii) putative virulence proteins and factors controlling their expression, and (iv) proteins produced by mobile elements. The macroarray was hybridized with the cellular DNAs of 80 S. aureus clinical isolates that were previously typed by analyses of their antibiograms and SmaI patterns. The set selected contained unrelated, endemic, and outbreak-related isolates belonging to 45 SmaI genotypes. In a gene content dendrogram, the 80 isolates were distributed into 52 clusters. The outbreak-related isolates were linked in the same or a closely related cluster(s). Clustering based on gene content provided a better discrimination than SmaI pattern analysis for the tested mecA(+) isolates that were endemic to Europe. All of the antibiotic resistance genes detected could be correlated with their corresponding phenotypes, except for one isolate which carried a mecA gene without being resistant. The 16 isolates responsible for bone infections were distinguishable from the 12 isolates from uninfected nasal carriers by a significantly higher prevalence of the sdrD gene coding for a putative SD (serine-aspartate) adhesin (in 15 and 7 isolates, respectively). In conclusion, the macroarray designed for this study offers an attractive and rapid typing method which has the advantage of providing additional information concerning the gene content of the isolate of interest.

Bacterial Proteins↗