Intraoperative dermoscopic features of onychomatricoma: a review of 10 cases.

BACKGROUND: Amelanotic nail tumours are difficult to diagnose. Dermoscopy is an accessible tool successfully used in diagnosis of amelanotic or melanotic skin tumours. We have previously shown the usefulness of dermoscopy in the preoperative diagnosis of onychomatricoma (OM). In this study, we completed this work by identifying additional intraoperative criteria to better establish the initial diagnosis of this tumour. AIMS: Evaluation of intraoperative dermoscopy in a small series of OM cases in order to define relevant diagnostic criteria. METHODS: In total, 10 patients with OM diagnosed in our centre were enrolled in the study. Six trained dermoscopists individually evaluated each criterion, then the data were compared and a consensus reached after discussion between the observers. For each criterion, we analysed its frequency and its interobserver accordance. We defined three architectural criteria (the 'Sagrada Familia' sign, digitations and the 'mirror sign'), and three vascular criteria (sagittal vessels, dotted vessels and irregular vessels). RESULTS: The Sagrada Familia sign, digitations and mirror sign were found in 100%, 90% and 70% of the cases, respectively, with high interobserver agreement. The vascular criteria were less regularly observed: sagittal, dotted and irregular vessels were respectively found in 80%, 70% and 50% of the OM cases, and were more difficult to assess, as shown by the lower interobserver agreement rates. CONCLUSION: Intraoperative dermoscopy of the nail matrix and bed offers useful information for the diagnosis and management of OM. Larger comparative studies should be performed to evaluate the true benefit of this approach.

COVA1-18 neutralizing antibody protects against SARS-CoV-2 in three preclinical models.

One year into the Coronavirus Disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), effective treatments are still needed 1-3 . Monoclonal antibodies, given alone or as part of a therapeutic cocktail, have shown promising results in patients, raising the hope that they could play an important role in preventing clinical deterioration in severely ill or in exposed, high risk individuals 4-6 . Here, we evaluated the prophylactic and therapeutic effect of COVA1-18 in vivo , a neutralizing antibody isolated from a convalescent patient 7 and highly potent against the B.1.1.7. isolate 8,9 . In both prophylactic and therapeutic settings, SARS-CoV-2 remained undetectable in the lungs of COVA1-18 treated hACE2 mice. Therapeutic treatment also caused a dramatic reduction in viral loads in the lungs of Syrian hamsters. When administered at 10 mg kg - 1 one day prior to a high dose SARS-CoV-2 challenge in cynomolgus macaques, COVA1-18 had a very strong antiviral activity in the upper respiratory compartments with an estimated reduction in viral infectivity of more than 95%, and prevented lymphopenia and extensive lung lesions. Modelling and experimental findings demonstrate that COVA1-18 has a strong antiviral activity in three different preclinical models and could be a valuable candidate for further clinical evaluation.