Drug specific cytotoxic T-cells in the skin lesions of a patient with toxic epidermal necrolysis

Toxic epidermal necrolysis is an extremely severe drug reaction, manifesting itself by widespread apoptosis of keratinocytes, generally considered to result from Fas/CD95-FasLigand interaction, but of unknown primary mechanism. We looked at the role of cells present in the skin blisters as probable effectors of this immune reaction. In a patient suffering from cotrimoxazole-induced toxic epidermal necrolysis, blister fluid cells were phenotyped by FACS and tested without prior restimulation for cytotoxicity on autologous and allogeneic cells in the presence of the drug. Blister fluid lymphocytes were predominantly CD8+, DR+, CLA+, CD56+ T lymphocytes, perforin positive and expressing preferentially two Vbeta chains of the T cell receptor repertoire. These lymphocytes were cytotoxic only in the presence of the drug towards autologous EBV transformed lymphocytes and towards allogeneic cells sharing HLA-Cw4. Cytotoxicity occurred in the presence of either cotrimoxazole, sulfamethoxazole, or the nitroso metabolite of sulfamethoxazole, but not with the hydroxylamine metabolite of sulfamethoxazole. The lysis was blocked by an anti-MHC class I monoclonal antibody. It was abolished by EGTA and CMA, but neither by anti-fas, brefeldin A, nor by anti-TRAIL receptor monoclonal antibodies, strongly suggesting perforin/granzyme-mediated cytotoxicity, without implication of Fas or TRAIL at this stage. This is direct evidence that T lymphocytes present within the lesions of toxic epidermal necrolysis may exhibit, without any re-stimulation, a drug-specific cytotoxicity against autologous cells. Harboring the markers of classical CTL and MHC class I restriction these lymphocytes reacted against the parent drug and one of its reactive metabolites. These results challenge several current concepts and could support new therapeutic approaches.     

Initial presentation of acute transverse myelitis in systemic lupus erythematosus: demographics, diagnosis, management and comparison to idiopathic cases

To describe and compare the diagnosis, demographics and management of systemic lupus erythematosus (SLE) related versus idiopathic acute transverse myelitis during the initial presentation of the disease. We undertook a chart review of the hospital records of patients admitted to our hospital from 1994 until 2007 and had the diagnosis of SLE related and idiopathic acute transverse myelitis. Demographics, laboratory and imaging studies, diagnosis and treatment were recorded in both groups and analyzed in a case control fashion. We identified 15 patients with SLE-related acute transverse myelitis (SLE-ATM) and 39 idiopathic (I-ATM) cases between 1994 and 2007. Patients with SLE were more likely to be African American, have CNS demyelinating lesions on MRI, a high IgG% on their CSF analysis and a higher sedimentation rate on presentation. Treatment with high-dose steroids was instituted in both groups of patients, though SLE patients had a longer hospital stay by an average of 5 days. SLE-ATM patients were more likely to be African American as compared to I-ATM patients, have CNS demyelinating lesions on MRI, a high IgG% on CSF analysis and a higher sedimentation rate on presentation. The hospital stay for SLE patients was 5 days longer than the idiopathic patients. This study underlines the importance of early diagnosis of patients who develop ATM related to SLE.     

CR1(CD35) and CR2(CD21) complement C3 receptors are expressed on normal human thymocytes and mediate infection of thymocytes with opsonized human immunodeficiency virus

The present study demonstrates that the C3b receptor CR1 (CD35) and the C3dg/Epstein-Barr virus receptor CR2 (CD21) are expressed by 25% and 70% of normal human thymocytes, respectively. The expression of CR2 extends to both CD1⁺ and CD1^? cells in the thymus. Two subsets of CR2⁺ thymocytes were defined expressing low and high density of the receptor. The CR2⁺⁺ subset represented 20% of CR2⁺ thymocytes and co-expressed the CR1 receptor. CR2⁺⁺ thymocytes expressed an immature CD1^dull, CD3^?, CD4^dull, CD8^?, CD7⁺⁺ phenotype and included a subpopulation of large cells expressing CD34. Twenty percent of thymocytes expressed the CD21 epitope defined by monoclonal antibody BU32, which is involved in the binding of CD23 to CD21. These observations provide a basis for a role for CD21 in the proliferation and differentiation of thymocytes at early stages of maturation. The functionality of CR1 and CR2 on thymocytes was evidenced by the ability of the receptors to mediate infection of cells with complement-opsonized human immunodeficiency virus (HIV). The results may be relevant to the immunopathogenesis of HIV infection.     

Febrile seizures. From molecular biology to clinical practice

Febrile seizures occur between the age of 3 months and 5 years with a temperature of 38 degrees C or higher, and are either simple or complex. Eight gene loci have been identified to be associated with certain cases of autosomal dominant familial febrile seizures, and 12 genes have been associated with some of the familial epilepsy syndromes that can start with febrile seizures. The mutations and the protein products are known for only some of these 20 genes. The risk of recurrence of convulsions in a further febrile illness is on average 30%, and of developing epilepsy is on average 6%, but both vary depending on the presence and number of risk factors in any given patient. The immediate treatment of a febrile convulsion is intravenous or rectal diazepam, but febrile status epilepticus requires intravenous Phenobarbital and possibly other medications. Long-term antiepileptic drugs are not recommended in most patients with febrile seizures. However, exceptions should be considered on an individual basis in patients with complex febrile seizures with multiple risk factors for development of later epilepsy.     

Neuroimaging manifestations and genetic heterogeneity of Walker-Warburg syndrome in Saudi patients

BackgroundWalker-Warburg syndrome (WWS), an autosomal recessive disease, is the most severe phenotype of congenital muscular dystrophies. Its diagnosis remains primarily clinical and radiological. Identification of its causative variants will assist genetic counseling. We aim to describe genetic and neuroimaging findings of WWS and investigate the correlation between them.MethodsWe retrospectively reviewed the clinical, genetic and neuroimaging findings of eleven Saudi neonates diagnosed with WWS between April 2012 and December 2018 in a single tertiary care center. Correlation between neuroimaging and genetic findings was investigated.ResultsAll patients had macrocephaly except one who had intrauterine growth restriction. Dysmorphic features were identified in nearly half of the patients. Creatine kinase levels were available in nine patients and were always elevated. Homozygous pathogenic variants were identified in all patients spanning POMT1 (n = 5), TMEM5 (n = 3), ISPD (n = 2) and POMT2 (n = 1) including one patient who had a dual molecular diagnosis of ISPD and PGAP2. On neuroimaging, all patients showed cobblestone cortex, classical infratentorial findings, and hydrocephalus. Other cerebral cortical malformations included subependymal heterotopia, polymicrogyria and open-lip schizencephaly in four, two and one patients, respectively. Buphthalmos and microphthalmia were the most prevalent orbital findings and found in all patients either unilaterally or bilaterally.ConclusionWWS is a genetically heterogeneous disorder among Saudis. The case with an additional PGAP2-related phenotype exemplifies the increased risk of dual autosomal recessive disorders in consanguineous populations. MRI is excellent in demonstrating spectrum of WWS brain and orbital malformations; however, no definite correlation could be found between the MRI findings and the genetic variant.     

The antiprotozoal activity of methylated flavonoids from Ageratum conyzoides L.

Aim of the study

The dichloromethane extract prepared from aerial parts of Ageratum conyzoides L. (Asteraceae), a plant commonly used in folk medicine for a number of illnesses including sleeping sickness, was recently found to exhibit a prominent activity (IC₅₀ = 0.78 μg/mL) against bloodstream forms of Trypanosoma brucei rhodesiense, the etiologic agent of East African Human Trypanosomiasis (East African Sleeping Sickness). This extract also exhibited noticeable activities against Leishmania donovani (Kala-Azar, IC₅₀ = 3.4 μg/mL) as well as Plasmodium falciparum (Malaria tropica, IC₅₀ = 8.0 μg/mL). In the current study, we sought for potentially active constituents of Ageratum conyzoides.

Materials and methods

Extracts prepared with solvents of different polarity were tested for activity against the above mentioned parasites as well as against Trypanosoma cruzi (Chagas’ disease) and for cytotoxicity using established protocols. The dicholoromethane extract showed the highest level of activity and was chosen for phytochemical studies aimed at the isolation of potential active constituents.

Results and conclusion

Five highly methoxylated flavonoids along with the chromene derivative encecalol methyl ether were isolated. All isolated compounds were previously reported from Ageratum conyzoides. While the chromene turned out to be inactive against the tested parasites, the flavonoids showed activity against the protozoan pathogens, some in the lower micromolar range. However, none of these isolated compounds was as active as the crude extract. This is the first report on antiprotozoal activity of this plant species and some of its constituents. The chemical principle accounting for the high activity of the crude extract, however, remains to be identified.     

Exposure to Vehicular Pollution and Assessment of Respiratory Function in Urban Inhabitants

Particulate matter less than PM₁₀ and aromatic chemicals formed during incomplete combustion of organic matter are major environmental pollutants because of their toxic potential. The present study reports on the respiratory morbidity pattern of people exposed to auto exhaust as a result of the traffic load consisting of three varieties of vehicles (heavy, medium, and light) at three different points: North (B), South (E), and Central (C) regions of Kolkata, India. Particle size distribution was analyzed by an Anderson cascade impactor and volatile organic compounds (VOCs) were analyzed by sorbent tube and capillary gas chromatography with flame ionization detector. Levels of VOCs, particularly benzene and toluene (at B, 15.2 and 20.1 μg/m³; at E, 67.4 and 74.6 μg/m³, and at C, 40.7 and 61.3 μg/m³, respectively), were found to be appreciably high in three sites in Kolkata compared with the values reported by the U.S. EPA. PM₁₀ concentrations also have been found to be higher than the Central Pollution Control Board of India’s permissible standard (≤10 μm: B, 535.9; E, 909.2; C, 1114.5 μg/m³; <10–3.3 μm: B, 269.8 μg/m³; E, 460.1; C, 679.2 μg/m³; and <3.3–0.4 μm: B, 266.1; E, 449.1; C, 435.3 μg/m³). Pulmonary function tests (PFT) of 505 inhabitants were performed in the three different areas using Spirovit SP-10 and Wrights peak flowmeter. The traffic load in the vicinity supported the occurrence of higher respiratory functional deterioration. PFT status showed restrictive (3.76%), obstructive (3.17%), and combined restrictive and obstructive types (1.98%) of impairment. Higher restrictive impairments in males might be due to their combined occupational and environmental exposures. The rate of increase of the number of vehicles on the roads of the city adds to the risk of greater problems due to exposure to hazardous substances that are less than PM₁₀, in particular, polycyclic aromatic hydrocarbons and VOCs. An erratum to this article can be found at     

Novel Marine Compounds: Anticancer or Genotoxic?

In the past several decades, marine organisms have generouslygifted to the pharmaceutical industries numerous naturallybioactive compounds with antiviral, antibacterial,antimalarial, anti-inflammatory, antioxidant, and anticancerpotentials. But till date only few anticancer drugs (cytarabine,vidarabine) have been commercially developed from marinecompounds while several others are currently in differentclinical trials. Majority of these compounds were tested in thetumor xenograft models, however, lack of anticancer potentialdata in the chemical- and/or oncogene-induced pre-initiationanimal carcinogenesis models might have cost some of the marineanticancer compounds an early exit from the clinical trials. Thisreview critically discusses importance of preclinicalevaluation, failure of human clinical trials with certainpotential anticancer agents, the screening tests used, and choiceof biomarkers.