Single-cell RNA sequencing uncovers the nuclear decoy lincRNA PIRAT as a regulator of systemic monocyte immunity during COVID-19.

The systemic immune response to viral infection is shaped by master transcription factors, such as NF-κB, STAT1, or PU.1. Although long noncoding RNAs (lncRNAs) have been suggested as important regulators of transcription factor activity, their contributions to the systemic immunopathologies observed during SARS-CoV-2 infection have remained unknown. Here, we employed a targeted single-cell RNA sequencing approach to reveal lncRNAs differentially expressed in blood leukocytes during severe COVID-19. Our results uncover the lncRNA PIRAT (PU.1-induced regulator of alarmin transcription) as a major PU.1 feedback-regulator in monocytes, governing the production of the alarmins S100A8/A9, key drivers of COVID-19 pathogenesis. Knockout and transgene expression, combined with chromatin-occupancy profiling, characterized PIRAT as a nuclear decoy RNA, keeping PU.1 from binding to alarmin promoters and promoting its binding to pseudogenes in naïve monocytes. NF-κB-dependent PIRAT down-regulation during COVID-19 consequently releases a transcriptional brake, fueling alarmin production. Alarmin expression is additionally enhanced by the up-regulation of the lncRNA LUCAT1, which promotes NF-κB-dependent gene expression at the expense of targets of the JAK-STAT pathway. Our results suggest a major role of nuclear noncoding RNA networks in systemic antiviral responses to SARS-CoV-2 in humans.

Diagnostic and therapeutic delays in lung cancer during the COVID-19 pandemic: a single center experience at a German Cancer center.

BACKGROUND: The COVID-19 pandemic has had negative drawbacks on the healthcare system worldwide and on individuals other than those directly affected by the virus. Delays in cancer therapy and diagnosis have been reported in the literature. We hypothesized similar effects on patients with lung cancer at our center. METHODS: We retrospectively analyzed data of patients referred to our center with newly diagnosed lung cancer from 2018 to 2022. We considered distribution of UICC Stages and time from case presentation in our multidisciplinary tumor board or from therapeutic indication from treating physician to therapy initiation (surgery, systemic therapies and radiation) to define delays in diagnosis and treatment. RESULTS: 1020 patients with newly diagnosed lung cancer were referred to our center from 2018 to 2022, with a median of 206 cases yearly (range: 200-208). Cases with Stage IV in 2020-2022 were significantly higher than in 2018-2019 (57% vs. 46%, p = 0,001). 228 operative resections took place between 2018 and 2022, 100 from January 2018 to February 2020 and 128 from March 2020 to December 2022. Median time from presentation in our tumor board to resection was also significantly longer after the beginning of the pandemic than before (22 days vs. 15,5 days, p = 0,013). No significant delays were observed for administration of systemic treatment and initiation of radiation. CONCLUSIONS: During the pandemic higher disease stages were reported for patients with lung cancer, yet there were no clinically relevant delays in treatment. In the context of the post-covid era new diagnostic strategies are necessary to facilitate early diagnosis of lung cancer. Despite the pandemic, for patients with suspicious symptoms prompt access to healthcare facilities is essential for early diagnosis.

Impaired systemic nucleocapsid antigen clearance in severe COVID-19.

The circulating nucleocapsid (NCP) antigen of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is detectable in coronavirus disease-2019 (COVID-19) patients. To better understand the biology of disease severity, we investigated NCP clearance kinetics in hospitalized COVID-19 patients. Serum NCP was quantified using a commercial NCP-specific enzyme-linked immunoassay in hospitalized COVID-19 patients (n = 63) during their hospital stay. Results were correlated to COVID-19 disease severity, inflammation parameters, antibody response, and results of SARS-CoV-2 PCR from nasopharyngeal swabs. We demonstrate that NCP antigen levels in serum remained elevated in 21/45 (46.7%) samples from patients in intensive care units (ICU) after >8 days postdiagnosis. The proportion of ICU patients with detectable antigenemia declined only gradually from 84.6% to 25.0% over several weeks. This was in contrast to complete NCP clearance in all non-ICU patients after 8 days, and also in contrast to mucosal clearance of the virus as measured by PCR. Antigen clearance was associated with higher IgG against S1 but not NCP. Clearance of NCP antigenemia is delayed in >40% of severely ill COVID-19 patients. Thus, NCP antigenemia detected after 8 days post COVID-19 diagnosis is a characteristic of patients requiring intensive care. Prospective trials should further investigate NCP antigen clearance kinetics as a mechanistic biomarker.

Regulation of fatty acid desaturase- and immunity gene-expression by mbk-1/DYRK1A in Caenorhabditis elegans.

BACKGROUND: In the nematode Caenorhabditis elegans, longevity in response to germline ablation, but not in response to reduced insulin/IGF1-like signaling, is strongly dependent on the conserved protein kinase minibrain-related kinase 1 (MBK-1). In humans, the MBK-1 ortholog DYRK1A is associated with a variety of disorders, most prominently with neurological defects observed in Down syndrome. To better understand mbk-1's physiological roles and their dependence on genetic background, we analyzed the influence of mbk-1 loss on the transcriptomes of wildtype and long-lived, germline-deficient or insulin-receptor defective, C. elegans strains by RNA-sequencing. RESULTS: mbk-1 loss elicited global changes in transcription that were less pronounced in insulin-receptor mutant than in germline-deficient or wildtype C. elegans. Irrespective of genetic background, mbk-1 regulated genes were enriched for functions in biological processes related to organic acid metabolism and pathogen defense. qPCR-studies confirmed mbk-1 dependent induction of all three C. elegans Δ9-fatty acid desaturases, fat-5, fat-6 and fat-7, in wildtype, germline-deficient and insulin-receptor mutant strains. Conversely, mbk-1 dependent expression patterns of selected pathogen resistance genes, including asp-12, dod-24 and drd-50, differed across the genetic backgrounds examined. Finally, cth-1 and cysl-2, two genes which connect pathogen resistance to the metabolism of the gaseous messenger and lifespan regulator hydrogen sulfide (H2S), were commonly suppressed by mbk-1 loss only in wildtype and germline-deficient, but not in insulin-receptor mutant C. elegans. CONCLUSION: Our work reveals previously unknown roles of C. elegans mbk-1 in the regulation of fatty acid desaturase- and H2S metabolic-genes. These roles are only partially dependent on genetic background. Considering the particular importance of fatty acid desaturation and H2S for longevity of germline-deficient C. elegans, we propose that these processes at least in part account for the previous observation that mbk-1 preferentially regulates lifespan in these worms.

Monitoring multiple myeloma in the peripheral blood based on cell-free DNA and circulating plasma cells.

With the advent of novel, highly effective therapies for multiple myeloma (MM), classical serologic monitoring appears insufficient for response assessment and prediction of relapse. Moreover, serologic studies in MM are hampered by interference of therapeutic antibodies. The detection of malignant plasma cell clones by next generation sequencing (NGS) or multiparameter flow cytometry (MFC) circumvents these difficulties and can be performed in the peripheral blood (pB) by targeting circulating cell-free DNA (cfDNA) or circulating plasma cells (CPCs), thus also avoiding an invasive sampling procedure. Here, we applied NGS of VJ light chain (LC) rearrangements in cfDNA and MFC of magnetically-enriched CD138-positive CPCs (me-MFC) to investigate disease burden in unselected MM patients. Sequencing was successful for 114/130 (87.7%) cfDNA samples and me-MFC results were analyzable for 196/205 (95.6%) samples. MM clones were detectable in 38.9% of samples taken at initial diagnosis or relapse (ID/RD), but only in 11.8% of samples taken during complete remission (CR). Circulating MM plasma cells were present in 83.3% of ID/RD samples and 9.9% of CR samples. Residual disease assessment by NGS or me-MFC in samples taken during very good partial remission or CR was 80% concordant. Notably, 4/4 (NGS) and 5/8 (me-MFC) positive CR samples were from patients with oligo- or non-secretory myeloma. The time to progression was shorter if there was evidence of residual myeloma in the pB. Together, our findings indicate that our two novel analytical approaches accurately indicate the course of MM and may be particularly valuable for monitoring patients with serologically non-trackable disease.

Expression of ß-1,4-galactosyltransferases during Aging in Caenorhabditis elegans.

BACKGROUND: Altered plasma activity of ß-1,4-galac-tosyl-transferases (B4GALTs) is a novel candidate biomarker of human aging. B4GALT1 is assumed to be largely responsible for this activity increase, but how it modulates the aging process is unclear at present. OBJECTIVES: To determine how expression of B4GALT1 and other B4GALT enzymes changes during aging of an experimentally tractable model organism, Caenorhabditis elegans. METHODS: Targeted analysis of mRNA levels of all 3 C. elegans B4GALT family members was performed by qPCR in wild-type and in long-lived daf-2 (insulin/IGF1-like receptor)-deficient or germline-deficient animals. RESULTS: bre-4 (B4GALT1/2/3/4) is the only B4GALT whose expression increases during aging in wild-type worms. In addition, bre-4 levels also rise during aging in long-lived daf-2-deficient worms, but not in animals that are long-lived due to the lack of germline stem cells. On the other hand, expression of sqv-3 (B4GALT7) and of W02B12.11 (B4GALT5/6) appears decreased or constant, respectively, in all backgrounds during aging. CONCLUSIONS: The age-dependent bre-4 mRNA increase in C. elegans parallels the age-dependent B4GALT activity increase in humans and is consistent with C. elegans being a suitable experimental organism to define potentially conserved roles of B4GALT1 during aging.

Comprehensive genetic diagnosis of acute myeloid leukemia by next-generation sequencing.

Differential induction therapy of all subtypes of acute myeloid leukemia other than acute promyelocytic leukemia is impeded by the long time required to complete complex and diverse cytogenetic and molecular genetic analyses for risk stratification or targeted treatment decisions. Here, we describe a reliable, rapid and sensitive diagnostic approach that combines karyotyping and mutational screening in a single, integrated, next-generation sequencing assay. Numerical karyotyping was performed by low coverage whole genome sequencing followed by copy number variation analysis using a novel algorithm based on in silico-generated reference karyotypes. Translocations and DNA variants were examined by targeted resequencing of fusion transcripts and mutational hotspot regions using commercially available kits and analysis pipelines. For the identification of FLT3 internal tandem duplications and KMT2A partial tandem duplications, we adapted previously described tools. In a validation cohort including 22 primary patients' samples, 9/9 numerically normal karyotypes were classified correctly and 30/31 (97%) copy number variations reported by classical cytogenetics and fluorescence in situ hybridization analysis were uncovered by our next-generation sequencing karyotyping approach. Predesigned fusion and mutation panels were validated exemplarily on leukemia cell lines and a subset of patients' samples and identified all expected genomic alterations. Finally, blinded analysis of eight additional patients' samples using our comprehensive assay accurately reproduced reference results. Therefore, calculated karyotyping by low coverage whole genome sequencing enables fast and reliable detection of numerical chromosomal changes and, in combination with panel-based fusion-and mutation screening, will greatly facilitate implementation of subtype-specific induction therapies in acute myeloid leukemia.

A rational two-step approach to KRAS mutation testing in colorectal cancer using high resolution melting analysis and pyrosequencing.

BACKGROUND: KRAS mutation testing is mandatory in the management of metastatic colorectal cancer prior to treatment with anti-EGFR antibodies as patients whose tumors express mutant KRAS do not benefit from these agents. Although the U.S. Food and Drug Administration has recently approved two in-vitro diagnostics kits for determination of KRAS status, there is generally no consensus on the preferred method and new tests are continuously being developed. Most of these techniques focus on the hotspot mutations at codons 12 and 13 of the KRAS gene. METHODS: We describe a two-step approach to KRAS codon 12/13 mutation testing involving high resolution melting analysis (HRM) followed by pyrosequencing using the Therascreen KRAS Pyro kit (Qiagen) of only those samples that are not clearly identified as KRAS wildtype or mutant by HRM. First, we determined KRAS status in a panel of 61 colorectal cancer samples using both methods to compare technical performance and concordance of results. Subsequently, we evaluated practicability and costs of our concept in an independent set of 120 colorectal cancer samples in a routine diagnostic setting. RESULTS: HRM and pyrosequencing appeared to be equally sensitive, allowing for clear detection of mutant alleles at a mutant allele frequency ≥12.5 %. Pyrosequencing yielded more exploitable results due to lower input requirements and a lower rate of analysis failures. KRAS codon 12/13 status was called concordantly for 98.2 % (56/57) of all samples that could be successfully analysed by both methods and 100 % (19/19) of samples that were identified mutant by HRM. Reviewing the actual effort and expenses for KRAS mutation testing in our laboratory revealed, that the selective use of pyrosequencing for only those samples that could not be analysed by HRM increased the fraction of valid results from 87.5 % for HRM alone to 99.2 % (119/120) while allowing for a net reduction of operational costs of >75 % compared to pyrosequencing alone. CONCLUSIONS: Combination of HRM and pyrosequencing in a two-step diagnostic procedure constitutes a reliable and economic analysis platform for KRAS mutation testing in colorectal cancer in a clinical setting.

[Precision medicine in oncology]. / Präzisionsmedizin in der Onkologie.

Personalized oncology according to current practice is primarily based on tumor biology, which is translated into genomic biomarkers. Mutations in oncogenes and tumor suppressor genes are targeted by rationally designed drugs and, conversely, are used to inform tailored treatment strategies. Faster and cheaper technologies for DNA sequencing enable genomic medicine in a clinical routine setting. Genomic features, tumor biology and clinical implications are integrated into individual therapy recommendations by molecular tumor boards, which have been established at many cancer centers in Germany and worldwide throughout recent years. This article discusses the promises and limitations of genomics-centered precision oncology and highlights future avenues and alternative approaches to individualize cancer treatment.

[Precision oncology and molecular tumor boards]. / Präzisionsonkologie und molekulare Tumorboards.

Precision oncology is a field of personalized medicine in which tumor biology forms the basis for tailored treatments. The preferred approach currently applied in clinical practice is based on the concept of malignant tumors as genetic diseases that are caused by mutations in oncogenes and tumor suppressors. On the one hand, these can be targeted by molecular drugs, while on the other hand, next-generation sequencing allows for comprehensive analysis of all relevant aberrations, thus enabling the matching of appropriate treatments across entities based on molecular information. Rational molecular therapies are developed and annotated with supporting evidence by molecular tumor boards, which have been established at various academic centers in recent years. Advancing precision oncology to a new standard of care requires improved applicability of personalized molecular therapies and thorough scientific evaluation of precision oncology programs.

NGS-Guided Precision Oncology in Breast Cancer and Gynecological Tumors-A Retrospective Molecular Tumor Board Analysis.

Background: Precision oncology treatments are being applied more commonly in breast and gynecological oncology through the implementation of Molecular Tumor Boards (MTBs), but real-world clinical outcome data remain limited. Methods: A retrospective analysis was conducted in patients with breast cancer (BC) and gynecological malignancies referred to our center's MTB from 2018 to 2023. The analysis covered patient characteristics, next-generation sequencing (NGS) results, MTB recommendations, therapy received, and clinical outcomes. Results: Sixty-three patients (77.8%) had metastatic disease, and forty-four patients (54.3%) had previously undergone three or more lines of systemic treatment. Personalized treatment recommendations were provided to 50 patients (63.3%), while 29 (36.7%) had no actionable target. Ultimately, 23 patients (29.1%) underwent molecular-matched treatment (MMT). Commonly altered genes in patients with pan-gyn tumors (BC and gynecological malignancies) included TP53 (n = 42/81, 51.9%), PIK3CA (n = 18/81, 22.2%), BRCA1/2 (n = 10/81, 12.3%), and ARID1A (n = 9/81, 11.1%). Patients treated with MMT showed significantly prolonged progression-free survival (median PFS 5.5 vs. 3.5 months, p = 0.0014). Of all patients who underwent molecular profiling, 13.6% experienced a major clinical benefit (PFSr ≥ 1.3 and PR/SD ≥ 6 months) through precision oncology. Conclusions: NGS-guided precision oncology demonstrated improved clinical outcomes in a subgroup of patients with gynecological and breast cancers.

[Clinically relevant molecular pathological diagnostics in breast cancer]. / Klinisch relevante molekularpathologische Diagnostik beim Mammakarzinom.

In breast cancer, the current guideline for pathological workup includes recommendations for advanced molecular analysis of certain predictive molecular markers in addition to basic immunohistochemical diagnostics. These markers are determined depending on tumor stage, including sequencing techniques and immunohistochemical methods. This comprises the systematic investigation of molecular alterations such as PIK3CA or BRCA1,2 mutations, NTRK fusions, or microsatellite instability as a basis for targeted therapy. Further alterations, for example in the PI3K pathway, ESR1 alterations, or ERBB2 mutations, may also be relevant for individual therapy decisions especially in the context of resistant or relapsed disease. Thus, particularly in advanced stages, a more comprehensive molecular characterization of the tumor may reveal genetic alterations that act as tumor drivers and provide targets for personalized therapies. Due to the large number of potential molecular targets, NGS panel diagnostics are a suitable approach in this conjunction with immunohistochemical characterization and the individual clinical situation. Molecular based therapeutical strategies outside of entity-specific approvals should be discussed in an interdisciplinary team within the framework of a molecular tumor board.

Serum proteomics hint at an early T-cell response and modulation of SARS-CoV-2-related pathogenic pathways in COVID-19-ARDS treated with Ruxolitinib.

Background: Acute respiratory distress syndrome (ARDS) in corona virus disease 19 (COVID-19) is triggered by hyperinflammation, thus providing a rationale for immunosuppressive treatments. The Janus kinase inhibitor Ruxolitinib (Ruxo) has shown efficacy in severe and critical COVID-19. In this study, we hypothesized that Ruxo's mode of action in this condition is reflected by changes in the peripheral blood proteome. Methods: This study included 11 COVID-19 patients, who were treated at our center's Intensive Care Unit (ICU). All patients received standard-of-care treatment and n = 8 patients with ARDS received Ruxo in addition. Blood samples were collected before (day 0) and on days 1, 6, and 10 of Ruxo treatment or, respectively, ICU admission. Serum proteomes were analyzed by mass spectrometry (MS) and cytometric bead array. Results: Linear modeling of MS data yielded 27 significantly differentially regulated proteins on day 1, 69 on day 6 and 72 on day 10. Only five factors (IGLV10-54, PSMB1, PGLYRP1, APOA5, WARS1) were regulated both concordantly and significantly over time. Overrepresentation analysis revealed biological processes involving T-cells only on day 1, while a humoral immune response and complement activation were detected at day 6 and day 10. Pathway enrichment analysis identified the NRF2-pathway early under Ruxo treatment and Network map of SARS-CoV-2 signaling and Statin inhibition of cholesterol production at later time points. Conclusion: Our results indicate that the mechanism of action of Ruxo in COVID-19-ARDS can be related to both known effects of this drug as a modulator of T-cells and the SARS-CoV-2-infection.

Autoantibodies are highly prevalent in non-SARS-CoV-2 respiratory infections and critical illness.

The widespread presence of autoantibodies in acute infection with SARS-CoV-2 is increasingly recognized, but the prevalence of autoantibodies in non-SARS-CoV-2 infections and critical illness has not yet been reported. We profiled IgG autoantibodies in 267 patients from 5 independent cohorts with non-SARS-CoV-2 viral, bacterial, and noninfectious critical illness. Serum samples were screened using Luminex arrays that included 58 cytokines and 55 autoantigens, many of which are associated with connective tissue diseases (CTDs). Samples positive for anti-cytokine antibodies were tested for receptor blocking activity using cell-based functional assays. Anti-cytokine antibodies were identified in > 50% of patients across all 5 acutely ill cohorts. In critically ill patients, anti-cytokine antibodies were far more common in infected versus uninfected patients. In cell-based functional assays, 11 of 39 samples positive for select anti-cytokine antibodies displayed receptor blocking activity against surface receptors for Type I IFN, GM-CSF, and IL-6. Autoantibodies against CTD-associated autoantigens were also commonly observed, including newly detected antibodies that emerged in longitudinal samples. These findings demonstrate that anti-cytokine and autoantibodies are common across different viral and nonviral infections and range in severity of illness.

The Low Expression of Fc-Gamma Receptor III (CD16) and High Expression of Fc-Gamma Receptor I (CD64) on Neutrophil Granulocytes Mark Severe COVID-19 Pneumonia.

Hyperinflammation through neutrophil granulocytes contributes to disease severity in COVID-19 pneumonia and promotes acute lung failure. Understanding the mechanisms of the dysregulations within the myeloid cell compartment may help to improve therapies for severe COVID-19 infection. Here, we investigated the immunopathological characteristics of circulating neutrophil granulocytes and monocytes in 16 patients with COVID-19 pneumonia by multiparameter flow cytometry in comparison to 9 patients with pulmonary infiltrates but without COVID-19. We correlated the immunophenotypes with the scores of the severity-of-disease classification system, APACHE-II. We found that the mean fluorescence intensity (MFI) of CD15, which is important for the transendothelial migration, was significantly reduced in the patients with COVID-19 (difference ± SD; 295.70 ± 117.50 MFI; p = 0.02). In addition, the granularity was significantly lower in the neutrophil granulocytes of patients with COVID-19 (difference ± SD; 1.11 ± 0.43 side-scatter ratio; p = 0.02). Moreover, the Fc-gamma receptor III (CD16) and Fc-gamma receptor I (CD64) on the neutrophil granulocytes were expressed discordantly with COVID-19 severity. CD16 correlated as inversely proportional (ρ = (-)0.72; 95% CI (-)0.92-(-)0.23; p = 0.01) and CD64 as proportional (ρ = 0.76; 95% CI 0.31-0.93; p = 0.01) with the APACHE-II scores of the patients. We conclude that the deviant expression of the Fc-gamma receptors might play role in a dysregulated antibody-mediated phagocytosis in severe cases of COVID-19 pneumonia.

A Bioinformatics View on Acute Myeloid Leukemia Surface Molecules by Combined Bayesian and ABC Analysis.

"Big omics data" provoke the challenge of extracting meaningful information with clinical benefit. Here, we propose a two-step approach, an initial unsupervised inspection of the structure of the high dimensional data followed by supervised analysis of gene expression levels, to reconstruct the surface patterns on different subtypes of acute myeloid leukemia (AML). First, Bayesian methodology was used, focusing on surface molecules encoded by cluster of differentiation (CD) genes to assess whether AML is a homogeneous group or segregates into clusters. Gene expressions of 390 patient samples measured using microarray technology and 150 samples measured via RNA-Seq were compared. Beyond acute promyelocytic leukemia (APL), a well-known AML subentity, the remaining AML samples were separated into two distinct subgroups. Next, we investigated which CD molecules would best distinguish each AML subgroup against APL, and validated discriminative molecules of both datasets by searching the scientific literature. Surprisingly, a comparison of both omics analyses revealed that CD339 was the only overlapping gene differentially regulated in APL and other AML subtypes. In summary, our two-step approach for gene expression analysis revealed two previously unknown subgroup distinctions in AML based on surface molecule expression, which may guide the differentiation of subentities in a given clinical-diagnostic context.

Further Extension of Lifespan by Unc-43/CaMKII and Egl-8/PLCß Mutations in Germline-Deficient Caenorhabditis elegans.

Reduction of insulin/insulin-like growth factor 1 (IGF1) signaling (IIS) promotes longevity across species. In the nematode Caenorhabditis elegans, ablation of germline stem cells (GSCs) and activity changes of the conserved signaling mediators unc-43/CaMKII (calcium/calmodulin-dependent kinase type II) and egl-8/PLCß (phospholipase Cß) also increase lifespan. Like IIS, these pathways depend on the conserved transcription factor daf-16/FOXO for lifespan extension, but how they functionally interact is unknown. Here, we show that altered unc-43/egl-8 activity further increases the lifespan of long-lived GSC-deficient worms, but not of worms that are long-lived due to a strong reduction-of-function mutation in the insulin/IGF1-like receptor daf-2. Additionally, we provide evidence for unc-43 and, to a lesser extent, egl-8 modulating the expression of certain collagen genes, which were reported to be dispensable for longevity of these particular daf-2 mutant worms, but not for other forms of longevity. Together, these results provide new insights into the conditions and potential mechanisms by which CaMKII- and PLCß-signals modulate C. elegans lifespan.

ESCMID COVID-19 guidelines: diagnostic testing for SARS-CoV-2.

SCOPE: The objective of these guidelines is to identify the most appropriate diagnostic test and/or diagnostic approach for SARS-CoV-2. The recommendations are intended to provide guidance to clinicians, clinical microbiologists, other health care personnel, and decision makers. METHODS: An ESCMID COVID-19 guidelines task force was established by the ESCMID Executive Committee. A small group was established, half appointed by the chair and the remaining selected with an open call. Each panel met virtually once a week. For all decisions, a simple majority vote was used. A list of clinical questions using the PICO (population, intervention, comparison, outcome) format was developed at the beginning of the process. For each PICO, two panel members performed a literature search focusing on systematic reviews, with a third panellist involved in case of inconsistent results. Quality of evidence assessment was based on the GRADE-ADOLOPMENT (Grading of Recommendations Assessment, Development and Evaluation - adoption, adaptation, and de novo development of recommendations) approach. RECOMMENDATIONS: A total of 43 PICO questions were selected that involve the following types of populations: (a) patients with signs and symptoms of COVID-19; (b) travellers, healthcare workers, and other individuals at risk for exposure to SARS-CoV-2; (c) asymptomatic individuals, and (d) close contacts of patients infected with SARS-CoV-2. The type of diagnostic test (commercial rapid nucleic acid amplification tests and rapid antigen detection), biomaterial, time since onset of symptoms/contact with an infectious case, age, disease severity, and risk of developing severe disease are also taken into consideration.