key: cord-1048901-vjfw0avj authors: Maaskant, Annemiek; Meijer, Lisette; Bakker, Jaco; van Geest, Leo; Zijlmans, Dian G.M.; Langermans, Jan A.M.; Verschoor, Ernst J.; Stammes, Marieke A. title: Bronchoalveolar lavage affects thorax computed tomography of healthy and SARS-CoV-2 infected rhesus macaques (Macaca mulatta) date: 2021-02-04 journal: bioRxiv DOI: 10.1101/2021.02.04.429761 sha: 5d553c9cf10ec0469ff1e0e484ac30d9b40dd2d6 doc_id: 1048901 cord_uid: vjfw0avj Medical imaging as method to assess the longitudinal process of a SARS-CoV-2 infection in non-human primates is commonly used in research settings. Bronchoalveolar lavage (BAL) is also regularly used to determine the local virus production and immune effects of SARS-CoV-2 in the lower respiratory tract. However, the potential interference of those two diagnostic modalities with each other is unknown in non-human primates. The current study investigated the effect and duration of BAL on computed tomography (CT) in both healthy and experimentally SARS-CoV-2-infected female rhesus macaques (Macaca mulatta). In addition, the effect of subsequent BALs was reviewed. Thorax CTs and BALs were obtained from four healthy animals and 11 experimentally SARS-CoV-2-infected animals. From all animals, CTs were obtained just before BAL, and 24 hours post-BAL. Additionally, from the healthy animals, CTs immediately after and four hours post-BAL were obtained. Thorax CTs were evaluated for alterations in lung density, measured in Hounsfield units, and a visual semi-quantitative scoring system. An increase in the lung density was observed on the immediately post-BAL CT but resolved within 24 hours in the healthy animals. In the infected animals, a significant difference in both the lung density and CT score was still found 24 hours after BAL. Furthermore, the differences between timepoints in CT score were increased for the second BAL. These results indicate that the effect of BAL on infected lungs is not completed within the first 24 hours. Therefore, it is of importance to acknowledge the interference between BAL and CT in rhesus macaques. such as cell counts and differential, cytopathologic analysis, and cultures in addition to specific 60 molecular and immunologic diagnostic tests (9). In COVID-19 research, it is predominantly used to 61 prove the presence of virus locally in the lungs. By combining swabs with a BAL, the majority of the 62 respiratory tract can be screened. Nevertheless, the utility of BAL in COVID-19 research or as 63 diagnostic procedure, in general, is arguable. A potential drawback of the use of BAL is the possibility 64 of artificial dissemination of SARS-CoV-2 and the impact on the readout of thorax CTs (13). In addition, 65 Geri et al. suggests that when the swabs of the upper respiratory tract and thorax CTs are negative it is 66 likely that the BAL is negative as well (16). Others state that BAL has a place in diagnosis of COVID-67 19 besides swabs and imaging or that, in vaccine testing, BAL is more robust and specific to demonstrate 68 reduction in viral load than in nasal swabs and more specific than the lesions found on thorax CTs (17- The study consisted of two groups of rhesus macaques; a non-infected group and a SARS-CoV-2 87 infected group. The study was conducted at the Biomedical Primate Research Centre (BPRC, Rijswijk, 88 The Netherlands). For the non-infected group, four healthy rhesus macaques were included. Three BAL 89 samples were taken to evaluate potential deleterious effects on the lung by using various thorax CTs. For the infected group 11 macaques were analyzed, derived from three different COVID-19 studies. These animals were selected out of those studies of which a CT was obtained before and 24 hours after All animals were of Indian origin, female rhesus macaques (Macaca mulatta), purpose bred at the 102 BPRC. During the study the animals were socially housed in pairs. All animals were between 7 and 16 103 years old and weighed between 6.2 to 11.5 kg. Cages for each pair of animals measured 1 x 2 x 2 meters 104 and were divided into different compartments that were freely accessible to allow animals the choice 105 where to sit. All cages were provided with bedding to allow foraging, environmental enrichment such 106 as fire hoses, mirrors and toys. Daily, all animals also received additional food enrichment items. All Before comparing the different groups and timepoints with each other, the entire group of animals was 187 examined for possible confounding factors in relation to age and weight. In correlation with both visual 188 and quantitative assessment no confounding factors were found for these parameters. The current study does not provide evidence of an increased percentage of retained fluid but 314 redistribution between the lung lobes due to coughing cannot be excluded. The differences found 315 between BAL 1 and BAL 2 suggest that the effect of these procedures is still ongoing 24 hours after 316 subsequent BALs, however not clearly visible. As BAL 3 was obtained four days after BAL 2, it was 16 not expected to find ongoing effects that could be related to BAL 2. By comparing all the outcome 318 parameters from BAL 1 with BAL 3 and BAL 2 with BAL 3 significant differences were not found. A familial cluster of pneumonia associated 2 Animal models of acute lung injury Animal models of mechanisms of SARS-CoV-2 infection and COVID-19 pathology Comparison of nonhuman primates identified the 401 suitable model for COVID-19 SARS-CoV-2 infection leads to acute infection with dynamic cellular and 403 inflammatory flux in the lung that varies across nonhuman primate species Comparison of SARS-CoV-2 infection in two non-human primate species: rhesus and cynomolgus 408 macaques Development of a Coronavirus Disease 2019 Nonhuman Primate Model Using Airborne 410 Exposure Bronchoalveolar lavage as a diagnostic procedure: a 412 review of known cellular and molecular findings in various lung diseases Bronchoalveolar lavage: sampling technique and guidelines for cytologic preparation and 414 interpretation Bronchoalveolar lavage fluid lymphocytosis in 104 dogs Bronchoalveolar lavage affects computed tomographic 418 and radiographic characteristics of the lungs in healthy dogs COVID-19-like abnormalities in CT-and PET/CT-imaged lungs of SARS-CoV-2-infected crab-eating macaques 421 (Macaca fascicularis) SARS-CoV-2 423 infection of African green monkeys results in mild respiratory disease discernible by PET/CT imaging and 424 shedding of infectious virus from both respiratory and gastrointestinal tracts Effect of 427 segmental bronchoalveolar lavage on quantitative computed tomography of the lung Limited role for 430 bronchoalveolar lavage to exclude COVID-19 after negative upper respiratory tract swabs: a multicentre study Usefulness of 433 bronchoalveolar lavage in suspect COVID-19 repeatedly negative swab test and interstitial lung disease Factors limiting the utility of bronchoalveolar lavage in the diagnosis of Covid-436 19 Single-shot Ad26 vaccine 438 protects against SARS-CoV-2 in rhesus macaques Detection of 2019 novel 450 coronavirus (2019-nCoV) by real-time RT-PCR Virological assessment 452 of hospitalized patients with COVID-2019 Chest CT in COVID-19: What the Radiologist Needs to Know Unilateral acid aspiration