Association of HLA-DP/DQ and STAT4 polymorphisms with ankylosing spondylitis in Southwest China

Ankylosing spondylitis (AS) is a highly heritable complex inflammatory arthritis disease. Genetic factors are thought to be crucial in the pathogenesis of AS. However, few data are available on the relationship between HLA-DP/DQ and STAT4 polymorphisms and AS susceptibility in the Chinese population. Therefore, we examined HLA-DP/DQ and STAT4 polymorphisms (rs3077, rs9277535, rs7453920 and rs7574865) in a total of 779 subjects, including 400 AS and 379 age- and sex-matched healthy controls in Chinese. No significant difference was observed between AS patients and healthy controls in the allele frequency of rs3077, rs9277535 and rs7574865. However, there was a significant association between the HLA-DQ rs7453920 G/A variant and AS patients, with minor allele A correlated with a reduced risk of AS (allelic frequency, adjusted OR = 0.66, 95% CI = 0.55–0.78, p = 4.0E − 06; dominant model, adjusted OR = 0.75, 95% CI = 0.66–0.85, p = 1.1E − 05). Moreover, the haplotypes block AAA and GGA in the HLA gene significantly correlated with reduced risk of AS. This is the first study demonstrating the significant associations of SNP rs7453920 and the haplotypes in the HLA gene with the risk of AS in Southwest Chinese population. This research sheds new light on the significant relationship between HLA polymorphisms and AS.     

Internalization of titanium dioxide nanoparticles by glial cells is given at short times and is mainly mediated by actin reorganization-dependent endocytosis

Many nanoparticles (NPs) have toxic effects on multiple cell lines. This toxicity is assumed to be related to their accumulation within cells. However, the process of internalization of NPs has not yet been fully characterized. In this study, the cellular uptake, accumulation, and localization of titanium dioxide nanoparticles (TiO₂ NPs) in rat (C6) and human (U373) glial cells were analyzed using time-lapse microscopy (TLM) and transmission electron microscopy (TEM). Cytochalasin D (Cyt-D) was used to evaluate whether the internalization process depends of actin reorganization. To determine whether the NP uptake is mediated by phagocytosis or macropinocytosis, nitroblue tetrazolium (NBT) reduction was measured and the 5-(N-ethyl-N-isopropyl)-amiloride was used. Expression of proteins involved with endocytosis and exocytosis such as caveolin-1 (Cav-1) and cysteine string proteins (CSPs) was also determined using flow cytometry.TiO₂ NPs were taken up by both cell types, were bound to cellular membranes and were internalized at very short times after exposure (C6, 30 min; U373, 2 h). During the uptake process, the formation of pseudopodia and intracellular vesicles was observed, indicating that this process was mediated by endocytosis. No specific localization of TiO₂ NPs into particular organelles was found: in contrast, they were primarily localized into large vesicles in the cytoplasm. Internalization of TiO₂ NPs was strongly inhibited by Cyt-D in both cells and by amiloride in U373 cells; besides, the observed endocytosis was not associated with NBT reduction in either cell type, indicating that macropinocytosis is the main process of internalization in U373 cells. In addition, increases in the expression of Cav-1 protein and CSPs were observed.In conclusion, glial cells are able to internalize TiO₂ NPs by a constitutive endocytic mechanism which may be associated with their strong cytotoxic effect in these cells; therefore, TiO₂ NPs internalization and their accumulation in brain cells could be dangerous to human health.     

Off-label use of tocilizumab for the treatment of SARS-CoV-2 pneumonia in Milan,Italy

BackgroundTocilizumab, a humanized monoclonal antibody, targets IL-6 receptors blocking downstream pro-inflammatory effects of IL-6. In preliminary reports it was suggested to be beneficial in patients with severe COVID-19.MethodsIn this open-label prospective study we describe clinical characteristics and outcome of 51 patients hospitalized with confirmed and severe COVID-19 pneumonia treated with tocilizumab intravenously. All patients had elevated IL-6 plasma level (>40 pg/mL) and oxygen saturation <93% in ambient air. Clinical outcomes, oxygen support, laboratory data and adverse events were collected over a follow-up of 30 days.ResultsForty-five patients (88%) were on high-flow oxygen supplementation, six of whom with invasive ventilation. From baseline to day 7 after tocilizumab we observed a dramatic drop of body temperature and CRP value with a significant increase in lymphocyte count (p<0.001). Over a median follow-up time of 34 days from tocilizumab, 34 patients (67%) showed an improvement in their clinical severity class; 31 were discharged; 17 (33%) showed a worsening of their clinical status, of these 14 died (27%). The mortality rate was significantly associated with mechanical ventilation at baseline (83.3% vs 20% of patients on non-invasive oxygen support; p=0.0001). The most frequent side effects were an increase of hepatic enzymes (29%), thrombocytopenia (14%), and serious bacterial and fungal infections (27%).ConclusionTocilizumab exerts a rapidly beneficial effect on fever and inflammatory markers, although no significant impact on the clinical outcome can be inferred by our results. Critically ill patients seem to have a high risk of serious infections with this drug.