COVID-19, chronic inflammatory rheumatic disease and anti-rheumatic treatments

Clinical Rheumatology - Since December 2019, the pandemic caused by coronavirus disease 2019 (COVID-19) raises a real public health problem. COVID-19 appeared in Wuhan (Hubei province) in China....     

Significant hybridization differences in comparative genomic hybridization due to nucleotides used for DNA labelling and to DNA chosen for cohybridization.

OBJECTIVE: Comparative genomic hybridization (CGH) has been established as an informative technique in genetic analysis. However, differences in the ratio of hybridization intensities were reported for particular chromosomes, which may affect CGH results. The aim of this study was to define these differences in more detail. For this purpose, CGH results of 70 samples of bone marrow cells (BMC) with normal karyotype in conventional cytogenetics (CC) were evaluated using seven different reference DNAs and two different DNA labeling systems. METHODS AND RESULTS: CGH using fluorochrome-conjugated nucleotides for DNA labeling indicated signal deviations in 21/70 BMC samples. Deviations affected chromosomes 1 (n = 21), 2 (n = 11), 4 (n = 11), 5 (n = 9), 6 (n = 7), 7 (n = 2), 8 (n = 2), 12 (n = 5), 13 (n = 15), 14 (n = 1), 16 (n = 17), 17 (n = 11), 19 (n = 21), 20 (n = 12), and/or 22 (n = 17). None of the imbalances were confirmed by fluorescence in situ hybridization (FISH). Using digoxigenin and biotin-conjugated nucleotides in exemplary cases (n = 5) led to the disappearance of the signal deviations. Repeated CGH experiments using seven different reference DNAs showed remarkable variations in the signal deviations. CONCLUSION: Hybridization differences depend not only on the hapten or fluorochrome-labeled nucleotides used for DNA labeling, but also on the reference DNA chosen. Therefore, close control of CGH experiments is mandatory, and additional techniques such as FISH should be performed to confirm the results obtained by CGH.     

T cell activation correlates with an increased proportion of antigen among the materials acquired from target cells

We have investigated the density of peptides required to elicit different biological responses in cytotoxic T lymphocytes (CTL), including trogocytosis (i.e., the phenomenon whereby the lymphocytes actively capture fragments of plasma membrane from those cells with which they establish an immune synapse). We have used two separate mouse models of CTL recognising defined peptides presented by MHC class I molecules. In both systems, triggering of cytotoxicity and capture of membrane components reached saturation with low densities of ligand. On the other hand, down-modulation of cell-surface levels of TCR, induction of IFN-gamma production and detection of peptide captured required much higher ligand densities. Interestingly, fratricide (i.e., killing between CTL sharing the same specificity), a mechanism proposed to account for CTL exhaustion, was detected only at antigen concentrations still well above that second threshold leading to full blown activation. Taken together, our results show that the different thresholds that govern the elicitation of different CTL functions correlate with different proportions of antigen among the target cell components being captured via trogocytosis.     

Multiple myeloma: the quality of care is linked to geographical and organisational determinants. A study in a French registry

Multiple myeloma is a haematological malignancy whose care is spread over several specialities and provided by centres that various sizes, which raises the issue of equal opportunities in care access. Incident cases of myeloma between 2008 and 2010 were exhaustively identified by the Poitou‐Charentes Cancer Registry. To ascertain the quality of care, the diagnosis, staging, and treatment administered were compared to international recommendations. Three hundred and sixty‐seven patients were included. The diagnostic procedure exhibited 98% compliance, the staging 58%, and treatment 89%. Concerning diagnostic and staging, non‐compliance with recommendations was associated to the failure to perform collegiate case assessments in multidisciplinary team (MDT) meetings [OR 2.15 (1.15–4.04)], care provided at a secondary centre, and a distance between home and the centre of 5–25 km [2.16 (1.06–4.40)] and 25–50 km [2.86 (1.37–6.01)]. Regarding treatment, non‐compliance with recommendations was associated with care provided at a secondary centre [5.28 (2.03–13.75)]. Finally, diagnosis, staging and treatment quality improved over time. This study underlines the need to improve the organisation of the healthcare offer, so that patients can receive the best possible care. MDT seems to be the main means to improve quality of care.