Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulins using chemiluminescence immunoassay and its correlation with neutralizing antibodies.

BACKGROUND: Neutralizing antibodies (NAbs) against SARS-CoV-2 infection have a pivotal role in protective immune response; however, their measurement requires specialized facilities. We evaluated the degree of correlation between NAbs and anti-SARS-CoV-2 IgG/total Ig antibodies detected by chemiluminescent immunoassay in asymptomatic and previously symptomatic SARS-CoV-2 patients. METHODS: A total of 1241 participants (previously symptomatic patients and asymptomatic individuals), who were screened for SARS-CoV-2 infection by RT-PCR or serology, were enrolled in our study. Sera were analyzed for the presence of anti-spike-1(S1)-SARS-CoV-2 IgG/total Ig antibodies, using Ortho Clinical Diagnostics, USA. A signal/cut-off value (S/CO) ≥ 1 was considered reactive. NAbs were measured in 103 random samples from groups using microneutralization assay, with titer ≥ 1:10 being considered positive. RESULTS: Asymptomatic (n = 229) and 261 previously symptomatic individuals with positive serology and negative RT-PCR were finally included. Significant higher anti-S1-IgG titers were seen in asymptomatic individuals (P < 0.0001). Conversely, anti-S1-total Ig titers were significantly higher in previously symptomatic (P < 0.0001). NAbs were detected in both groups, however, higher titers were seen in previously symptomatic patients. There is a correlation between NAbs and both IgG/total anti-S1-SARS-CoV-2 antibodies (r = 0.47, P < 0.0001 and r = 0.49, P < 0.0001, respectively). IgG and total Ig could predict a neutralization titer of ≥ 1:160 at S/CO >4.44 and >65 with AUC 0.69 and 0.67, respectively. CONCLUSION: Asymptomatic SARS-CoV-2 infection can produce comparable antibodies response to previously symptomatic individuals, however higher neutralization activity was seen in the previously symptomatic. Anti-S1-SARS-CoV-2 IgG/total Ig antibodies showed a correlation with neutralization activity and can be used to estimate the presence of protective immunity.

Prevalence of SARS-CoV-2 infection and dynamics of antibodies response among previously undiagnosed healthcare workers in a university hospital: A prospective cohort study.

BACKGROUND: Healthcare workers (HCWs) are a presumed high-risk population for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Identifying factors associated with seroprevalence can help establish better practices in healthcare settings. In this study, we evaluate prevalence of SARS-CoV-2 infection among previously undiagnosed HCWs and describe profiling of antibody responses against SARS-CoV-2, including neutralizing antibodies (NAbs). METHODS: We analyzed a cohort of 386 HCWs in a university hospital in Egypt and 725 volunteers not affiliated to any healthcare facility (non-healthcare workers - NHCWs). Participants provided a nasopharyngeal swab and serum samples for SARS-CoV-2 nucleic acid and SARS-CoV-2-specific antibodies, respectively. HCWs who tested positive by either test were sequentially monitored. RESULTS: At baseline, point prevalence of viral carriage was 11.4% in HCWs (n = 44/386) and 11.9% in NHCWs (86/725). The cumulative prevalence of SARS-CoV-2 infection among HCWs considering all studies was 25.6%, which was statistically lower than in NHCWs (41.0%). Prevalence was greatest among janitorial staff (45.9%) and the most affected departments were gastroenterology (31.1%), and emergency medicine (30.0%). Prior anosmia, fever or headache were associated with higher odds of positivity for SARS-CoV-2 infection. Regarding serial antibody measurements, RT-PCR-positive HCWs displayed IgG detection rates of 29.5%, 70% and 60% at visit 1, visit 2 and visit 3, respectively with slow decline of median IgG antibody titers, whereas, corresponding detection rates for total Ig antibodies were 50%, 90.3%, and 88.9%, respectively with increasing median titers. NAbs measured at each time point were positively correlated with total Ig levels, whereas IgG levels were positively correlated with NAbs at visit 1 and visit 3. CONCLUSION: Our results demonstrate lower cumulative prevalence of SARS-CoV-2 infection in HCWs than general population and suggest that asymptomatic HCWs exhibit considerable IgG and total Ig antibodies response as well as NAbs for up to 120 days, with positive correlation in between.

SARS-CoV-2 infection among asymptomatic healthcare workers of the emergency department in a tertiary care facility.

BACKGROUND: Healthcare workers (HCWs) represent a high-risk category during the coronavirus disease 2019 (COVID-19) pandemic crisis, with frontline HCWs at emergency departments (EDs) may be at an even higher risk. Determining the spread of infection among HCWs may have implications for infection control policies in hospitals. This study aimed to detect severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection among asymptomatic HCWs of the ED of a large tertiary center in Cairo, Egypt. METHODS: The study was conducted from June 1st to June 14th, 2020. All the recommended national and international indications on infection control measures were followed. Two hundred and three HCWs were included in the study and tested by nasopharyngeal swab (NPS) and rapid serological test (RST). Descriptive statistical analyses were used to summarize the data. RESULTS: Of the 203 HCWs, 29 (14.3 %) tested positive by real-time reverse transcription polymerase chain reaction (RT-PCR). Thirty-seven (18.2 %) HCWs tested positive with RST: 20 with both IgM and IgG; 14 with IgM only, and 3 with IgG only. Age, gender, and/or occupation were not risk factors for SARS-CoV-2 infection. CONCLUSIONS: Point prevalence of COVID-19 in asymptomatic HCWs in ED of tertiary care facility is 14.3 % by RT-PCR. This illustrates the importance of screening all HCWs regardless of symptoms, and the need for strict measures in securing HCWs to reduce transmission from healthcare facilities to the community during the current pandemic.

SARS-CoV-2 infection among healthcare workers of a gastroenterological service in a tertiary care facility.

BACKGROUND AND STUDY AIMS: Frontlines healthcare workers (HCWs) during the coronavirus disease 2019 (COVID-19) pandemic are at increased risk of infection by SARS-CoV-2, but there are limited data on the prevalence of COVID-19 among HCWs in Egypt. This study aimed to assess SARS-CoV-2 infection among HCWs providing gastroenterological services. SUBJECTS AND METHODS: Seventy-four HCWs at the gastroenterological service of Al-Manial University Hospital, the main hospital of the largest tertiary university hospitals complex in Egypt (Kasr Al-Ainy Faculty of Medicine, Cairo University) were tested using real-time reverse transcription-polymerase chain reaction (RT-PCR) on nasopharyngeal samples, and rapid serological IgM/IgG tests (RST). A questionnaire was used to collect demographic, occupational and clinical data. RESULTS: Of the 74 HCWs, 10 tested positive by RT-PCR (13.5%). In 9/74 (12.2%) HCWs, antibodies could be detected by RST: three with both IgM and IgG lines; six with IgM line only and none with IgG line only. Frequency of positive tests was more among subjects with minor symptoms compared to completely asymptomatic HCWs (50% vs 16.1%, respectively). Neither age, gender or occupation was a risk factor for SARS-CoV-2 infection. CONCLUSIONS: Point prevalence of COVID-19 in gastroenterology HCWs is 13.5% by RT-PCR. Continued measures are warranted to assure HCWs safety and reduce transmission from healthcare settings to the community during COVID-19 pandemic. Presence of positive test results among asymptomatic HCWs illustrates the importance of screening all HCWs irrespective of symptoms.

Genotype Mutations in Egyptian Children with Familial Mediterranean Fever: Clinical Profile, and Response to Colchicine.

BACKGROUND: Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder that is characterized by recurrent episodes of fever, peritonitis, pleuritis, pericarditis, and/or arthritis. MEFV is the responsible gene for FMF, of which more than 310 mutations have been reported; M694V, M694I, V726A, E148Q, and M680I mutations are the five most frequent mutations responsible for the majority of FMF patients in the Middle East. AIM: To study the genetic background of FMF among Egyptian children to detect the most frequent MEFV mutations and to study the response of colchicine therapy with different gene mutations. METHODS: This cross-sectional study included 109 pediatric patients already diagnosed clinically with FMF, and were following-up at the Rheumatology Outpatient Clinic, Children's Hospital, Cairo University. RESULTS: Out of 109 patients, 95 had positive-MEFV mutation (87.16%), of which the most frequent mutations were E148Q (24/95 patients, 25.26%), V726A (19/95 patients, 20%), M680I (19/95 patients, 20%), M694V (17/95 patients, 17.89%), and M694I (7 patients, 7.37%). A better response to colchicine therapy was noted in E148Q mutation; on the other hand, more severe cases were reported with M694V mutations. CONCLUSION: E148Q, V726A, M680I, M694V and M694I mutations are the most frequent mutations denoting the heterogeneous mutation pattern and the milder form of the disease among Egyptian patients. M694V mutations may indicate a more severe disease score.

Free radical grafting kinetics of acrylamide onto a blend of starch/chitosan/alginate.

Grafting of monomer onto polymer backbone is one of the effective and accessible methods for the chemical modification of polysaccharides. Grafting of acrylamide (AAm) onto polysaccharides blend (PsB) composed of starch, chitosan and alginate has been carried out using potassium persulfate (KPS) as an initiator. The kinetics of the grafting polymerization also has been studied. The grafting parameters have been evaluated by changing the initial concentrations of AAm from 8 to 16 g, PsB from 6 to 14 g and KPS from 0.2 to 1 g. Evidence of grafting has been obtained from FTIR, XRD and TGA. The kinetics of the grafting polymerization also has been studied. The grafting rate equation of the produced hydrogel (PsB-g-AAm) hydrogel has been expressed by: Rg=k[AAm] [PsB](0.5) [KPS](0.5). The grafting rate is a first order dependence to [AAm] initial concentration and square root to [PsB] and [KPS] initial concentrations in the used concentrations range.

The expanded clinical profile and the efficacy of colchicine therapy in Egyptian children suffering from familial Mediterranean fever: a descriptive study.

BACKGROUND: Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by self-limiting recurrent attacks of fever and serosal inflammation, leading to abdominal, thoracic or articular pain. OBJECTIVE: To detect variable clinical presentations and genotypic distribution of different groups of FMF patients and the efficacy of colchicine therapy in treatment of these groups of FMF after one year. METHODS: A cross-sectional study was conducted on 70 patients already diagnosed with FMF and following-up at the Rheumatology Clinic, Children's Hospital - Cairo University. Diagnosis of FMF was determined according to Tel Hashomer criteria for FMF. All patients were subjected to a questionnaire including detailed history with emphasis on clinical manifestations and colchicine dose to control attacks. Mutational analysis was performed for all study subjects covering 12 mutations in the MEFV gene: E148Q, P369S, F479L, M680I (G/C), M680I (G/A), I692del, M694V, M694I, K695R, V726A, A744S and R761H. Response to colchicine treatment was evaluated as complete, incomplete and unresponsive. RESULTS: Out of the 70 patients- 40 males and 30 females- fever was the most common presenting feature, followed by abdominal pain, and arthritis; documented in 95.7%, 94.3%, and 77.1% of cases respectively. Mutational analysis detected gene mutation on both alleles in 20 patients (homozygotes), on only 1 allele in 40 patients (heterozygotes), and on none of the alleles (uncharacterized cases). Mild to moderate disease severity score (according to Tel Hashomer key to severity score) was detected in a significant proportion of heterozygotes and the uncharacterized group than the homozygotes. All patients received colchicine therapy; 22.9% of them showed complete response, 74.3% showed incomplete response and 2.9% showed no response to therapy. The colchicine dose needed to control attacks was significantly lower in heterozygotes than the homozygotes(P=0.04). Also patients' response to colchicine therapy was significantly better in the heterozygous group(P=0.023). CONCLUSION: Fever, abdominal pain and arthritis are the most common presenting features for homozygous, Heterozygous and uncharacterized patients. E148Q, V726A, and M680I were the most common mutations detected in the heterozygous group. Homozygosity were found for M680I, M694V, and M694I mutations in 13 patients (65% of homozygotes). Heterozygotes presenting with severe phenotype should be further analyzed for less common second MEFV mutation using gene sequencing. The colchicine dose required to control the attacks was significantly lower and patients' response to colchicine therapy was significantly better in the heterozygous group than homozygous group.