ABSTRACT
Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.
Subject(s)
COVID-19 Testing , COVID-19/diagnosis , Hospitalization , Adult , Aged , Antibodies, Viral/blood , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Prospective Studies , RNA, Viral/analysis , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Sensitivity and SpecificityABSTRACT
BACKGROUND: There are few studies to compare antibody response against anti-spike (S) and anti- nucleoprotein (N) SARS-CoV-2. OBJECTIVE: The aim of this study was to evaluate the IgG antibody production against S and N antigens of the virus and their correlation with the time and severity of the disease. METHODS: The IgG antibodies against S and N antigens of SARS-CoV-2 in serum specimens of 72 symptomatic patients who tested real-time reverse transcription polymerase chain reaction positive for SARS-CoV-2 were detected using the ELISA technique. Different antibody response was compared and the correlation with the time from disease onset and the severity was evaluated. RESULTS: Forty-eight of 72 (67%) patients tested positive for anti-SARS-CoV-2 antibodies, while 24 (33%) did not have detectable antibodies. Comparison of antibody levels for N and S antibodies showed that they correlate with each other well (r= 0.81; P< 0.001). However, sensitivity of anti-S SARS-CoV-2 IgG and anti-N SARS-CoV-2 IgG was 30% and 60%, during the first 7 days after symptom onset (r= 0.53; P= 0.111), but increased to 73% and 68% at more than 1-week post symptom onset (r= 0.89, P= 0.111), respectively. Cases with positive IgG response showed a decreased CD8+ T cells percentage compared to the negative IgG groups (26 ± 14 vs. 58 ± 32, p= 0.066 in anti-N IgG group and 28 ± 15 vs. 60 ± 45, p= 0.004 in anti-S IgG group, respectively). CONCLUSION: Nearly one-third of the confirmed COVID-19 patients had negative serology results. Lower percent positivity at early time points after symptom onset (less than 1 week) was seen using anti-S SARS-COV-2 IgG kit compare to the anti-N SARS-CoV-2 IgG; therefore, clinicians should interpret negative serology results of especially anti-S SARS-CoV-2 IgG with caution.
Subject(s)
COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , Immunoglobulin G/analysis , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , CD8-Positive T-Lymphocytes/immunology , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Humans , Lymphocyte Subsets/immunology , Male , Middle Aged , Negative Results , Real-Time Polymerase Chain Reaction , Sensitivity and Specificity , Severity of Illness IndexABSTRACT
BACKGROUND: The melanoma-associated antigen (MAGE) genes families are found in different cancers, including non-small-cell lung cancers. These genes are silent in normal tissues, except for the testis. The goal of this study was to investigate the differentially expressed profile of the different MAGE genes subclass in non-small-cell lung cancer (NSCLC) tumoral tissue. METHODS: Formalin-fixed paraffin embedded NSCLC resected tissues were collected from 31 patients hospitalized in our referral hospital, and 29 patients were diagnosed with either squamous cell carcinoma (SCC) or adenocarcinoma (ADC). We used a nested reverse transcriptase-polymerase chain reaction, which comprised independent amplification of MAGE-A1, MAGE-A2, MAGE-A3/6, MAGE-A4, and MAGE-A12, to detect expression frequency of the MAGE-A family in lung tissue biopsies at both tumoral and nontumoral parts of patients' tissues. RESULTS: From 29 patients with diagnosis of either SCC (n = 16) or ADCs (n = 13), 58 samples were prepared. From 58 blocks sampled for this experiment, 37 tumoral tissue samples and 22 nontumoral tissue samples expressed at least one of the MAGE-A genes. MAGE-A4 gene had the highest incidence among all MAGE-A genes in both tumoral and nontumoral gens. In SCC and ADCs, the data showed expression of at least one of the MAGE-A genes in 59.4% and 69.2% of tumoral and nontumoral tissues, respectively. CONCLUSION: The detection of the MAGE-A genes expression could be a molecular tumor marker for early diagnosis and potential targets for active immunotherapy in NSCLC, particularly in ADCs and SCC. Besides, the frequency of different subtypes of MAGE genes may vary in different regions of world.
