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1.
J Clin Virol ; 153: 105216, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1882173

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-sense, single-stranded RNA virus that causes coronavirus disease 2019 (COVID-19). Symptoms are variable and range from asymptomatic or mild to severe (i.e., pneumonia) in both healthy and immunocompromised patients. We developed a reverse-transcription droplet digital PCR (RT-ddPCR) assay for quantification of SARS-CoV-2 RNA in clinical nasopharyngeal and oropharyngeal swab specimens and evaluated the assay, including reproducibility, agreement of results, analytical measurement range, linearity, analytical sensitivity, and analytical specificity. This quantitative assay had a LoD of 218 copies/mL of viral transport media, with a linear quantification range from 500 to 5,000,000 copies/mL (R2 of 0.9817 and 0.9853 for N1 and N2 targets, respectively). Qualitative agreement of categorical results was 90.5% (57/63) between the reference and RT-ddPCR assays. Quantitative agreement between the two assays showed correlation, with R2 of 0.9726 and 0.9713 for N1 and N2 targets, respectively. No cross-reactivity with common coronavirus strains was detected. This SARS-CoV-2 quantitative RT-ddPCR assay may be a useful tool for a variety of applications including identification of patients with low viral load and serial monitoring of viral load in respiratory tracts specimens of patients for evaluation of the efficacy of therapy for COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Humans , Nasopharynx , RNA, Viral/analysis , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Reproducibility of Results , SARS-CoV-2/genetics , Sensitivity and Specificity
2.
Clinica chimica acta|international journal of clinical chemistry ; 2022.
Article in English | EuropePMC | ID: covidwho-1837538

ABSTRACT

Background SARS-CoV-2 is an RNA virus that causes primarily causes respiratory disease;however, infection of other tissue has been reported. Evaluation of SARS-CoV-2 in tissue specimens may increase understanding of SARS-CoV-2 pathobiology. Materials and Methods A qualitative test for detection of SARS-CoV-2 in formalin-fixed paraffin-embedded (FFPE) tissues was developed and validated using droplet digital PCR (ddPCR), which has a lower limit of detection than reverse transcription (RT)-qPCR. After extraction of total RNA from unstained FFPE tissue, SARS-CoV-2 nucleocapsid (N1, N2) target sequences were amplified and quantified, along with human RPP30 as a control using the Bio-Rad SARS-CoV-2 ddPCR kit. Results SARS-CoV-2 was detected in all 21 known positive samples and none of the 16 negative samples. As few as approximately 5 viral copies were reliably detected. Since January 2021, many tissue types have been clinically tested. Of the 195 clinical specimens, the positivity rate was 35% with placenta and fetal tissue showing the highest percentage of positive cases. Conclusion This sensitive FFPE-based assay has broad clinical utility with applications as diverse as pregnancy loss and evaluation of liver transplant rejection. This assay will aid in understanding atypical presentations of COVID-19 as well as long-term sequelae.

3.
Archives of Pathology & Laboratory Medicine ; 145(7):785-796, 2021.
Article in English | ProQuest Central | ID: covidwho-1338028

ABSTRACT

* Context.-Small case series have evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection in formalin-fixed, paraffin-embedded tissue using reverse transcription-polymerase chain reaction, immunohistochemistry (IHC), and/or RNA in situ hybridization (RNAish). [...]acute respiratory distress syndrome has been found in 3.4% of patients with COVID-19 and 72% to 93% of patients with COVID-19 who died.1-3 Furthermore, we and others have shown that acute bronchopneumonia, diffuse alveolar damage (DAD), aspiration pneumonia, and thromboemboli are common findings in the lungs of these patients at autopsy.4-9 Although evidence suggests that COVID-19 also impacts other organs such as heart,9 liver,9 and kidneys,9,10 the virus has so far been identified with certainty only in the lungs and rarely the brain, heart, liver, kidney, placenta, and blood by electron microscopy, immunohistochemistry (IHC), in situ hybridization (ISH), and reverse transcription-polymerase chain reaction (RT-PCR).8'9'11-18 Infection with SARS-CoV-2 is usually identified by the detection of viral RNA using RT-PCR on nasopharyngeal or oropharyngeal swabs. Furthermore, viral cytopathic effects and inclusions observed in cytomegalovirus, herpes simplex virus, and adenovirus infections are not evident in SARS-CoV-2 infections. [...]a formalin-fixed, paraffin-embedded (FFPE) tissue-based test is needed to establish the diagnosis of COVID-19 and guide management of the patient. Potential regional or temporal heterogeneity in viral genomic sequence due to genetic selection or drift may play a similar role, impacting the ability of existing targeted PCR assays to detect the virus in specimens from patients with COVID-19. Because formalin fixation can impact the quality and integrity of nucleic acid, sensitivity for the detection of microorganisms by PCR or other techniques may also be limited.

4.
Arch Pathol Lab Med ; 145(7): 785-796, 2021 07 01.
Article in English | MEDLINE | ID: covidwho-1134421

ABSTRACT

CONTEXT.­: Small case series have evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection in formalin-fixed, paraffin-embedded tissue using reverse transcription-polymerase chain reaction, immunohistochemistry (IHC), and/or RNA in situ hybridization (RNAish). OBJECTIVE.­: To compare droplet digital polymerase chain reaction, IHC, and RNAish to detect SARS-CoV-2 in formalin-fixed, paraffin-embedded tissue in a large series of lung specimens from coronavirus disease 2019 (COVID-19) patients. DESIGN.­: Droplet digital polymerase chain reaction and RNAish used commercially available probes; IHC used clone 1A9. Twenty-six autopsies of COVID-19 patients with formalin-fixed, paraffin-embedded tissue blocks of 62 lung specimens, 22 heart specimens, 2 brain specimens, and 1 liver, and 1 umbilical cord were included. Control cases included 9 autopsy lungs from patients with other infections/inflammation and virus-infected tissue or cell lines. RESULTS.­: Droplet digital polymerase chain reaction had the highest sensitivity for SARS-CoV-2 (96%) when compared with IHC (31%) and RNAish (36%). All 3 tests had a specificity of 100%. Agreement between droplet digital polymerase chain reaction and IHC or RNAish was fair (κ = 0.23 and κ = 0.35, respectively). Agreement between IHC and in situ hybridization was substantial (κ = 0.75). Interobserver reliability was almost perfect for IHC (κ = 0.91) and fair to moderate for RNAish (κ = 0.38-0.59). Lung tissues from patients who died earlier after onset of symptoms revealed higher copy numbers by droplet digital polymerase chain reaction (P = .03, Pearson correlation = -0.65) and were more likely to be positive by RNAish (P = .02) than lungs from patients who died later. We identified SARS-CoV-2 in hyaline membranes, in pneumocytes, and rarely in respiratory epithelium. Droplet digital polymerase chain reaction showed low copy numbers in 7 autopsy hearts from ProteoGenex Inc. All other extrapulmonary tissues were negative. CONCLUSIONS.­: Droplet digital polymerase chain reaction was the most sensitive and highly specific test to identify SARS-CoV-2 in lung specimens from COVID-19 patients.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Immunohistochemistry , In Situ Hybridization/methods , Lung/virology , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2/isolation & purification , Adult , Aged , Aged, 80 and over , COVID-19/virology , Female , Humans , Male , Middle Aged , Observer Variation , Prospective Studies , RNA, Viral/isolation & purification , Reproducibility of Results , SARS-CoV-2/genetics , Sensitivity and Specificity
5.
Circulation ; 143(3): 230-243, 2021 01 19.
Article in English | MEDLINE | ID: covidwho-1039948

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its resultant clinical presentation, coronavirus disease 2019 (COVID-19), is an emergent cause of mortality worldwide. Cardiac complications secondary to this infection are common; however, the underlying mechanisms of such remain unclear. A detailed cardiac evaluation of a series of individuals with COVID-19 undergoing postmortem evaluation is provided, with 4 aims: (1) describe the pathological spectrum of the myocardium; (2) compare with an alternate viral illness; (3) investigate angiotensin-converting enzyme 2 expression; and (4) provide the first description of the cardiac findings in patients with cleared infection. METHODS: Study cases were identified from institutional files and included COVID-19 (n=15: 12 active, 3 cleared), influenza A/B (n=6), and nonvirally mediated deaths (n=6). Salient information was abstracted from the medical record. Light microscopic findings were recorded. An angiotensin-converting enzyme 2 immunohistochemical H-score was compared across cases. Viral detection encompassed SARS-CoV-2 immunohistochemistry, ultrastructural examination, and droplet digital polymerase chain reaction. RESULTS: Male sex was more common in the COVID-19 group (P=0.05). Nonocclusive fibrin microthrombi (without ischemic injury) were identified in 16 cases (12 COVID-19, 2 influenza, and 2 controls) and were more common in the active COVID-19 cohort (P=0.006). Four active COVID-19 cases showed focal myocarditis, whereas 1 case of cleared COVID-19 showed extensive disease. Arteriolar angiotensin-converting enzyme 2 endothelial expression was lower in COVID-19 cases than in controls (P=0.004). Angiotensin-converting enzyme 2 myocardial expression did not differ by disease category, sex, age, or number of patient comorbidities (P=0.69, P=1.00, P=0.46, P=0.65, respectively). SARS-CoV-2 immunohistochemistry showed nonspecific staining, whereas ultrastructural examination and droplet digital polymerase chain reaction were negative for viral presence. Four patients (26.7%) with COVID-19 had underlying cardiac amyloidosis. Cases with cleared infection had variable presentations. CONCLUSIONS: This detailed histopathologic, immunohistochemical, ultrastructural, and molecular cardiac series showed no definitive evidence of direct myocardial infection. COVID-19 cases frequently have cardiac fibrin microthrombi, without universal acute ischemic injury. Moreover, myocarditis is present in 33.3% of patients with active and cleared COVID-19 but is usually limited in extent. Histological features of resolved infection are variable. Cardiac amyloidosis may be an additional risk factor for severe disease.


Subject(s)
COVID-19 , Coronary Thrombosis , Fibrin/metabolism , Myocardium , SARS-CoV-2/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/biosynthesis , COVID-19/metabolism , COVID-19/mortality , COVID-19/pathology , Child , Child, Preschool , Coronary Thrombosis/metabolism , Coronary Thrombosis/mortality , Coronary Thrombosis/pathology , Female , Gene Expression Regulation, Enzymologic , Humans , Immunohistochemistry , Infant , Male , Middle Aged , Myocardium/metabolism , Myocardium/pathology
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