Exploratory assessment of serological tests to determine antibody titer against SARS‐CoV‐2: Appropriateness and limits

BackgroundSerological tests can be used to detect antibodies in the serum of subject''s after SARS‐CoV‐2 infection and vaccination. Currently, variability in antibody titers and the availability of a multiplicity of serological tests have made it necessary to highlight their appropriateness and limitations in various diagnostic settings.MethodsThis study is part of Covidiagnostix, a multicenter project aimed at the assessment of the health technology used in SARS‐CoV‐2 serological tests. Based on data gained from the analysis of over 5000 subjects, a selected number of serum samples, representative of different diagnostic settings, were analyzed first by qualitative immunoassays (IgA, M, and G MILLIPLEX^® SARS‐CoV‐2 tests based on Luminex^®) to define the immunoglobulins serum composition and subsequently by four serological diagnostic tests (Elecsys Anti‐SARS‐CoV‐2 and Elecsys Anti‐SARS‐CoV‐2 S by Roche, SARS‐CoV‐2 IgG by Siemens Healthcare, and CHORUS SARS‐CoV‐2 “NEUTRALIZING” Ab by DIESSE). The first WHO International Standard for SARS‐CoV‐2 was also analyzed using the same methods.ResultsThis study evaluated the antibody content and titer of the WHO Standard and serum of subjects with/without previous infection and before/after vaccination for SARS‐CoV‐2.ConclusionThe definition of antibodies in the WHO standard and the analysis of serum samples allowed for the identification of the appropriateness of serological tests in each diagnostic setting, increasing the effectiveness of the resulting laboratory data. Furthermore, we found that it would be optimal to produce new international standards against the S1 domain and RBD of the SARS‐CoV‐2 spike protein for a more effective serological monitoring of vaccination.     

Nucleocapsid protein of SARS‐CoV‐2 is a potential target for developing new generation of vaccine

BackgroundSARS‐CoV‐2 has spread worldwide causing more than 400 million people with virus infections since early 2020. Currently, the existing vaccines targeting the spike glycoprotein (S protein) of SARS‐CoV‐2 are facing great challenge from the infection of SARS‐CoV‐2 virus and its multiple S protein variants. Thus, we need to develop a new generation of vaccines to prevent infection of the SARS‐CoV‐2 variants. Compared with the S protein, the nucleocapsid protein (N protein) of SARS‐CoV‐2 is more conservative and less mutations, which also plays a vital role in viral infection. Therefore, the N protein may have the great potential for developing new vaccines.MethodsThe N protein of SARS‐CoV‐2 was recombinantly expressed and purified in Escherichia coli. Western Blot and ELISA assays were used to demonstrate the immunoreactivity of the recombinant N protein with the serum of 22 COVID‐19 patients. We investigated further the response of the specific serum antibodies and cytokine production in BALB/c mice immunized with recombinant N protein by Western Blot and ELISA.ResultsThe N protein had good immunoreactivity and the production of IgG antibody against N protein in COVID‐19 patients was tightly correlated with disease severity. Furthermore, the N protein was used to immunize BALB/c mice to have elicited strong immune responses. Not only high levels of IgG antibody, but also cytokine‐IFN‐γ were produced in the N protein‐immunized mice. Importantly, the N protein immunization induced a high level of IgM antibody produced in the mice.ConclusionSARS‐CoV‐2 N protein shows a great big bundle of potentiality for developing a new generation of vaccines in fighting infection of SARS‐CoV‐2 and its variants.     

SARS‐CoV‐2, HIV,and Mycobacterium tuberculosis triple co‐infection

Tuberculosis (TB)‐related death has increased for the first time in a decade due to the coronavirus disease 2019 (COVID‐19), globally. People living with HIV (PLWHIV) might be at a higher risk of developing COVID‐19‐related complications. Herein, we describe the first case of a patient surviving from SARS‐CoV‐2‐TB‐HIV triple co‐infection in Cameroon. A 36‐year‐old Cameroonian woman presented at the emergency unit of the Jamot Hospital, Yaoundé with symptoms of anorexia, productive cough, weight loss, and fever. The SARS‐CoV‐2 rapid antigen test on nasopharyngeal sample was positive. Chest X‐ray showed bilateral parenchymal and tracheal calcifications most consistent with prior pulmonary histoplasmosis, varicella, or TB. She was tested HIV positive, and the sputum sample tested positive for TB on auramine staining. TB therapy (rifampicin, isoniazid, pyrazinamide, and ethambutol) and COVID‐19 treatment were initiated, and the symptoms improved after 2 weeks of treatment. The SARS‐CoV‐2 rapid antigen and real‐time polymerase chain reaction tests were negative after 2 weeks. She was discharged home on antiretroviral therapy and TB therapy. Coinfection with both TB, HIV, and SARS‐CoV‐2 may be common in Cameroon but not reported. The similar clinical features of COVID‐19 and TB usually lead to misdiagnosis. Early diagnosis and initiation of appropriate treatment improve outcome.     

COVID‐19 vaccine‐related new‐onset lichen planus

Coronavirus disease 2019 (COVID‐19) vaccines significantly impacted world health and well‐being. However, various adverse events have been observed following severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccination. Cutaneous reactions have been prevalent following many vaccines, including COVID‐19 vaccines. Here, we present a case of new‐onset lichen planus in a patient who received the COVID‐19 vaccine at the same time as being infected with SARS‐CoV‐2. A 52‐year‐old woman presented to the clinic with extensive pruritic skin lesions. The eruptions had appeared a week after her second dose of the Sinopharm COVID‐19 vaccine. She mentioned a history of SARS‐CoV‐2 infection approximately 10 days following the first dose of her vaccine, causing a 1‐month delay in getting the second dose. Her past medical history was not significant. On examination, erythematous and squamous papules were demonstrated predominantly on the extremities, including inguinal and axillary folds. Moreover, desquamation of the lips was visible, and buccal lesions were also found. After consultation with a dermatologist, a skin biopsy was indicated for the patient, but she refused to undergo the procedure. Therefore, considering the typical appearance of the eruptions, lichen planus was suspected, for which she was treated with oral antihistamines and topical corticosteroids.     

Co‐infection of Klebsiella pneumonia,Cytomegalovirus, Aspergillus and Zygomycete in a patient with SARS‐CoV‐2

Co‐infection between severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and other pathogens has become a serious threat. There are the reports of fungal, bacterial, and viral co‐infections with SARS‐CoV‐2. We report the unusual case of concomitant aspergillosis, mucormycosis, cytomegalovirus pneumonia, and also klebsiella pneumoniae empyema as the complication of SARS‐CoV‐2.     

New‐onset pemphigus foliaceus following SARS‐CoV‐2 infection and unmasking multiple sclerosis: A case report

Development of pemphigus foliaceus (PF) following SARS‐CoV‐2 infection has only been reported in one patient who had received Bamlanivimab and thus might be considered as a drug‐induced case of PF. Here, we reported the first case of PF arising solely after COVID infection without taking any culprit drug.     

Prolonged SARS‐Cov‐2 shedding with rapid IgG antibody decay in a COVID‐19 patient: A case report

BackgroundThe coronavirus disease 2019 (COVID‐19) epidemic is still spreading rapidly around the world. Recent cases with prolonged severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) RNA detection have been successively reported, and the phenomenon of false‐negative real‐time polymerase chain reaction (RT‐PCR) results of SARS‐CoV‐2 RNA or “repositive” was also described in COVID‐19 patients.MethodsWe report a 69‐year‐old female patient with hypertension, suspected lung tumor, and previous history of total hysterectomy for hysteromyoma who presented with moderate COVID‐19 symptoms and was positive for SARS‐CoV‐2 RNA by RT‐PCR when she traveled from the USA to China.ResultsThe patient required second and third re‐hospitalizations due to “repositive” SARS‐CoV‐2 throat swab test results during post‐charge solitary isolation and observation, and serum SARS‐CoV‐2‐IgG decayed rapidly before disappearing on illness Day 139 when the throat swab was still positive. The virus shedding lasted for at least 146 days (the last positive throat swab test result was on illness Day 146, and the first true‐negative test result was on illness Day 151) since her initial positive test.ConclusionProlonged SARS‐CoV‐2 RNA viral shedding is prone to occur in an immunocompromised host, wherein changes in the host immune status can lead to repeated positive SARS‐CoV‐2 detection. Moreover, the SARS‐CoV‐2‐IgG may decrease rapidly and disappear before virus removal, indicating there may be certain limitations on the protective effect of the SARS‐CoV‐2 antibody, which deserves clinical attention.     

The utility of SARS‐CoV‐2 nucleocapsid protein in laboratory diagnosis

BackgroundThe Coronavirus Disease 2019 (COVID‐19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), which has now become a global pandemic owing to its high transmissibility. The SARS‐CoV‐2 nucleocapsid protein tests are playing an important role in screening and diagnosing patients with COVID‐19, and studies about the utility of SARS‐CoV‐2 nucleocapsid protein tests are increasing now.MethodsIn this review, all the relevant original studies were assessed by searching in electronic databases including Scopus, Pubmed, Embase, and Web of Science. “SARS‐CoV‐2”, “COVID‐19”, “nucleocapsid protein”, and “antigen detection” were used as keywords.ResultsIn this review, we summarized the utility of SARS‐CoV‐2 nucleocapsid protein in laboratory diagnosis. Among the representative researches, this review analyzed, the sensitivity of SARS‐CoV‐2 nucleocapsid protein detection varies from 13% to 87.9%, while the specificity could almost reach 100% in most studies. As a matter of fact, the sensitivity is around 50% and could be higher or lower due to the influential factors.ConclusionIt is well suggested that SARS‐CoV‐2 nucleocapsid protein is a convenient method with a short turnaround time of about half an hour, and the presence of N antigen is positively related to viral transmissibility, indicating that SARS‐CoV‐2 N protein immunoassays contribute to finding out those infected people rapidly and segregating them from the uninfected people.     

Performance evaluation of three automated quantitative immunoassays and their correlation with a surrogate virus neutralization test in coronavirus disease 19 patients and pre‐pandemic controls

BackgroundSARS‐CoV‐2 pandemic is currently ongoing, meanwhile vaccinations are rapidly underway in some countries. The quantitative immunoassays detecting antibodies against spike antigen of SARS‐CoV‐2 have been developed based on the findings that they have a better correlation with the neutralizing antibody.MethodsThe performances of the Abbott Architect SARS‐CoV‐2 IgG II Quant, DiaSorin LIAISON SARS‐CoV‐2 TrimericS IgG, and Roche Elecsys anti‐SARS‐CoV‐2 S were evaluated on 173 sera from 126 SARS‐CoV‐2 patients and 151 pre‐pandemic sera. Their correlations with GenScript cPass SARS‐CoV‐2 Neutralization Antibody Detection Kit were also analyzed on 173 sera from 126 SARS‐CoV‐2 patients.ResultsArchitect SARS‐CoV‐2 IgG II Quant and Elecsys anti‐SARS‐CoV‐2 S showed the highest overall sensitivity (96.0%), followed by LIAISON SARS‐CoV‐2 TrimericS IgG (93.6%). The specificities of Elecsys anti‐SARS‐CoV‐2 S and LIAISON SARS‐CoV‐2 TrimericS IgG were 100.0%, followed by Architect SARS‐CoV‐2 IgG II Quant (99.3%). Regarding the correlation with cPass neutralization antibody assay, LIAISON SARS‐CoV‐2 TrimericS IgG showed the best correlation (Spearman rho = 0.88), followed by Architect SARS‐CoV‐2 IgG II Quant and Elecsys anti‐SARS‐CoV‐2 S (all rho = 0.87).ConclusionsThe three automated quantitative immunoassays showed good diagnostic performance and strong correlations with neutralization antibodies. These assays will be useful in diagnostic assistance, evaluating the response to vaccination, and the assessment of herd immunity in the future.     

SARS‐CoV‐2 and guttate psoriasis: A case report and review of literature

Guttate psoriasis is a rare dermatological presentation of SARS‐CoV‐2 infection and is seen mainly in patients with an underlying disease psoriasis.     

Hypersensitivity in the lungs is responsible for acute respiratory failure in COVID‐19 patients: Case series of patients who received high‐dose/short‐term methylprednisolone

BackgroundCOVID‐19 is a highly contagious respiratory disease caused by the SARS‐CoV‐2 virus. Patients with severe disease have a high fatality rate and face a huge medical burden due to the need for invasive mechanical ventilation. Hypoxic respiratory failure is the major cause of death in these patients. There are currently no specific anti‐SARS‐CoV‐2 drugs, and the effect of corticosteroids is still controversial.MethodsThe clinical data of 102 COVID‐19 patients, including 27 patients with severe disease, were analyzed. The serum levels of total IgE and anti‐SARS‐CoV‐2 specific IgE were compared in healthy controls and COVID‐19 patients, changes in the level of anti‐SARS‐CoV‐2 specific IgE and clinical response to methylprednisolone (MP) treatment were analyzed, and the effect of high‐dose/short‐term MP therapy for patients with critical illness and respiratory failure was determined.ResultsCOVID‐19 patients had elevated serum levels of anti‐SARS‐CoV‐2 specific IgE, and patients with severe disease, especially critical illness, had even higher levels. Application of short‐term/high‐dose MP significantly reduced the level of these IgE antibodies and also blocked the progression of hypoxic respiratory failure. Hypoxic respiratory failure in patients with COVID‐19 is related to pulmonary hypersensitivity.ConclusionsHypersensitivity in the lungs is responsible for acute respiratory failure in COVID‐19 patients. Application of high‐dose/short‐term MP appears to be an effective life‐saving method for COVID‐19 patients who have hypoxic respiratory failure.     

Orbital inflammatory disease following mRNA SARS‐CoV‐2 vaccine

A 65‐year‐old woman reported orbital symptoms two days after her first dose and presented exacerbation of signs after the second dose of BNT162b2 mRNA vaccine. The temporal relationship between the COVID‐19 vaccination and orbital symptoms suggests a probable link between SARS‐CoV‐2 mRNA vaccine and this orbital inflammatory disease.     

Recombinant subunits of SARS‐CoV‐2 spike protein as vaccine candidates to elicit neutralizing antibodies

ObjectivesThe spike protein has been reported as one of the most critical targets for vaccine design strategies against the SARS‐CoV‐2 infection. Hence, we have designed, produced, and evaluated the potential use of three truncated recombinant proteins derived from spike protein as vaccine candidates capable of neutralizing SARS‐CoV‐2 virus.MethodsIn silico tools were used to design spike‐based subunit recombinant proteins (RBD (P₁), fusion peptide (P₂), and S1/S2 cleavage site (P₃)). These proteins were checked for their ability to be identified by the anti‐SARS‐CoV‐2 antibodies by exposing them to COVID‐19 serum samples. The proteins were also injected into mice and rabbit, and the antibody titers were measured for 390 days to assess their neutralization efficiency.ResultsThe antibodies that existed in the serum of COVID‐19 patients were identified by designed proteins. The anti‐spike antibody titer was increased in the animals injected with recombinant proteins. The VNT results revealed that the produced antibodies could neutralize the cultured live virus.ConclusionTruncated subunit vaccines could also be considered as robust tools for effective vaccination against COVID‐19. Using a combination of in silico, in vitro, and in vivo experiments, it was shown that the injection of spike‐based truncated recombinant proteins could stimulate long‐lasting and neutralizing antibody responses.     

Longitudinally extensive transverse myelitis (LETM) secondary to SARS‐CoV‐2 infection: A recent reality in spinal cord injury rehabilitation

Transverse myelitis can be a complication of SARS‐CoV‐2 infection. We report the case of a transverse myelitis related to SARS‐CoV‐2 infection. Beyond the disease itself, neurological involvement affects functionality. In this situation, physical and rehabilitation medicine plays a crucial role in managing patient rehabilitation.     

SARS‐CoV‐2 omicron variant may present with severe sickle cell painful crisis: A report of two cases

Coronavirus disease 2019 (COVID‐19) is a respiratory viral illness that is caused by coronavirus 2 (SARS‐CoV‐2). The disease often presents with non‐specific symptoms such as fever, headache, and fatigue, accompanied by respiratory symptoms (e.g., cough and dyspnea) and other systemic involvement. Currently, the virus had shown significant changes and mutations that resulted in the emergence of different strains. Each strain varies in its virulence, disease severity, and the response of the body''s immune system. Sickle cell disease characterized by hemolytic anemia particularly in associated with stress. Patients with sickle cell disease infected with SARS‐CoV‐2 are reported to have increased risk for hospitalization, thrombosis, and other complications compared with non‐sickle cell patients. The Omicron variant causes mild disease in general population; however, in patients with sickle cell disease, the data are limited. We present two patients known to have sickle cell disease presented with a severe acute painful crisis that required hospitalization after infection with Omicron variant of the SARS‐CoV‐2 virus.     

The Hologic Aptima SARS‐CoV‐2 assay enables high ratio pooling saving reagents and improving turnaround time

BackgroundThe Hologic Aptima™ TMA SARS‐CoV‐2 assay was employed to test pooled nasopharyngeal (NP) samples to evaluate the performance of pooled sample testing and characterize variables influencing results.MethodsResults on 1033 previously tested NP samples were retrieved to characterize the relative light units (RLU) of SARS‐CoV‐2‐positive samples in the tested population. The pooling strategy of combining 10 SARS‐CoV‐2 samples into one pool (10/1) was used in this study. The results were compared with neat sample testing using the same Aptima™ TMA SARS‐CoV‐2 assay and also the CDC RT‐PCR and the Cepheid SARS‐CoV‐2 assays.ResultsThe Aptima assay compares favorably with both CDC RT‐PCR and the Cepheid SARS‐CoV‐2 assays. Once samples are pooled 10 to 1 as in our experiments, the resulting signal strength of the assay suffers. A divide opens between pools assembled from strong‐positive versus only weak‐positive samples. Pools of the former can be reliably detected with positive percent agreement (PPA) of 95.2%, while pools of the latter are frequently misclassified as negative with PPA of 40%. When the weak‐positive samples with kRLU value lower than 1012 constitute 3.4% of the total sample profile, the assay PPA approaches 93.4% suggesting that 10/1 pooled sample testing by the Aptima assay is an effective screening tool for SARS‐CoV‐2.ConclusionPerforming pooled testing, one should monitor the weak positives with kRLU lower than 1012 or quantification cycle (Cq) value higher than 35 on an ongoing basis and adjust pooling approaches to avoid reporting false negatives.