[Benralizumab in cases of eosinophilic granulomatosis with polyangiitis]. / Diagnostic d'une granulomatose éosinophilique avec polyangéite sous benralizumab.

INTRODUCTION: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare necrotizing vasculitis affecting small vessels and associated with severe asthma and eosinophilia. Monoclonal antibodies blocking the IL-5 signaling pathway, one example being benralizumab, decrease the proliferation of eosinophils and represent an effective treatment in severe eosinophilic asthma. They are a therapeutic option currently studied for EGPA. We report the paradoxical clinical case of EGPA appearing following the initiation of treatment with benralizumab (anti-IL-5R monoclonal antibody). CASE REPORT: We describe the case of a 66-year-old female patient with severe asthma. Following the initiation of benralizumab, she showed deterioration of her general condition, associated with severe peripheral neuropathy of the lower limbs. At the same time, she developed massive hypereosinophilia. After an extensive workup, the patient was eventually diagnosed with an EGPA with multisystem involvement. Benralizumab was stopped and a course of high dose corticosteroids and immunosuppressants was initiated, enabling slow clinical recovery. CONCLUSION: Anti-IL5 monoclonal antibodies, including benralizumab, are being investigated for new therapeutic indications, including EGPA. Paradoxically, a few rare cases of EGPA associated with these molecules have been reported in the literature. The causal link of this association remains hypothetical. Close monitoring of patients on benralizumab consequently seems indispensable.

Electrokinetic and hydrodynamic properties of sarcoplasmic reticulum vesicles: a study by laser Doppler electrophoresis and quasi-elastic light scattering.

The electrical properties of sarcoplasmic reticulum vesicles were studied using electrophoretic mobility measurements by laser Doppler velocimetry. Combined with quasi-elastic light scattering analysis, this method enabled us to monitor changes in membrane surface charge density upon addition of NaCl, CaCl2, and MgCl2 solutions. At low ionic strength (4.7 mM), and in the absence of divalent salts, sarcoplasmic reticulum vesicles displayed a zeta potential value of -32.6 mV and a surface charge density of 5.4 10(-3) C/m2, corresponding to one elementary negative charge per 30 nm2 or about 2900 negative charges per vesicle. Upon addition of NaCl (up to 100 mM) vesicles became more negative (from 2900 to 6200 negative charges per vesicle), suggesting chloride binding or adsorption on the membrane. A noticeable increase of the vesicular size was observed upon addition of calcium or magnesium (25 to 30% increase of the hydrodynamic radius for 2.5 mM CaCl2 or MgCl2). This effect was prevented or suppressed by addition of relatively low concentrations of NaCl (50 mM). At low divalent cation concentrations one-third of the total net charge of the vesicles was neutralized suggesting a specific binding of cation on the membrane. At higher salt concentrations no modification of this parameter was observed. These results support the Gouy and Chapman theory about the electrical properties of sarcoplasmic reticulum vesicles.

Design of a chemiluminescent and bioluminescent photometer.

An apparatus for chemi- and bioluminescence measurements is described. The main features are in high sensitivity: for example, 5 10(-12) M adenosine triphosphate, 5 10(-7) M glucose, 2 10(-9) M perhydrol and 4 10(-13) M peroxidase are easily detected; its fast mixing time and the possibility of injecting a reactant, at any time, enabling kinetic studies. Moreover, its compactness and 12 V battery supply allow measurements outside of laboratories.