Relationship between Disease Severity, Immune Response, and Viral Clearance in Unvaccinated Patients with COVID-19: A Cross-sectional Study
Introduction: The clinical manifestations of Coronavirus Disease-2019 (COVID-19) range from asymptomatic cases to severe respiratory failure. It is unclear whether disease severity is determined by an excess viral load or a dysregulated immune response. It is also unclear whether the severe immu...
Main Authors: | , , , , , |
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Format: | Article |
Language: | English |
Published: |
JCDR Research and Publications Private Limited
2023-12-01
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Series: | Journal of Clinical and Diagnostic Research |
Subjects: | |
Online Access: | https://www.jcdr.net/articles/PDF/18788/63744_CE[Ra1]_F(SL)_QC&Ref(SD_SL)_PF1(VD_OM)_redo(VD_OM)_PFA(OM)_PN(OM).pdf |
Summary: | Introduction: The clinical manifestations of Coronavirus
Disease-2019 (COVID-19) range from asymptomatic cases to
severe respiratory failure. It is unclear whether disease severity
is determined by an excess viral load or a dysregulated immune
response. It is also unclear whether the severe immune response
is successful in rapid viral clearance.
Aim: To understand the relationship between immune response,
viral clearance, and the severity of illness in unvaccinated
patients suffering from COVID-19.
Materials and Methods: This was a cross-sectional observational
study of 65 unvaccinated patients suffering from Reverse
Transcriptase-Polymerase Chain Reaction (RT-PCR) confirmed
COVID-19, conducted at a dedicated COVID-19 centre, Dr. D.Y.
Patil Hospital, Pimpri, Pune, Maharashtra, India. from September
2020 to April 2021. The subjects were enrolled between day
10 and day 14 of the onset of symptoms and from two distinct
clinical groups. Group A consisted of 34 mild cases, and Group B
consisted of 31 severe cases, classified according to the national
guidelines issued by the Indian Council of Medical Research
(ICMR). The clinical progress of the illness and laboratory test
records were carefully reviewed. A repeat throat swab for Severe
Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) RTPCR, blood levels of COVID-19 specific antibodies Immunoglobin
G (IgG) and IgM, C-reactive protein (CRP), and D-dimer levels
were measured on day 14 of the illness. The data were analysed
using MedCalc and Epi Info software. Chi-square and Fisher’sExact tests were used to assess variables such as viral detection,
antibody response, and inflammatory markers.
Results: In Group A, 2/34 (5.88%) patients tested RT-PCR
negative {Cycle threshold (Ct) value cut-off above 35} compared
to 5/31 (16.13%) in Group B (p=0.0829). In Groups A and B,
respectively, the mean antibody titers were 35390.47 and
36426.11 (p=0.7469), the mean CRP values were 4.91 (p<0.001)
and 31.01 mg/dL, and the mean D-dimer levels were 895 and
2896 ng/mL (p<0.001).
Conclusion: Both mild and severe COVID-19 cases had a
significant antibody response which, however, did not help in
viral clearance. Most patients remained RT-PCR positive on day
14 regardless of the disease severity. |
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ISSN: | 2249-782X 0973-709X |