Overexpression and purification of a recombinant chimeric HIV type 2/HIV type 1 envelope peptide and application in an accelerated immunobased HIV type 1/2 antibody detection system (AIBS): a new rapid serological screening assay

Transfusion transmitted infections in frequently transfused thalassemic children living in Fayoum Governorate, Egypt: Current prevalence and risk factors

Regular blood transfusion therapy remains the primary treatment in thalassemia major (TM). Transfusion-transmitted infections (TTIs) and iron overload are considered to be the major drawbacks of this therapy. This cross-sectional study aimed to update the prevalence of the hepatitis C virus (HCV) antibody, PCR-confirmed HCV, hepatitis B surface antigen (HBsAg), and human immunodeficiency virus (HIV) antibody among TM children. Clinical and epidemiological factors that can affect HCV infection prevalence rate were studied. This study evaluated 121 children with βTM, including 61 males and 60 females with a mean age of 7.99±3.57years. Patients were evaluated for the HCV, HBsAg, and HIV-1 & 2 antibodies. All tests were performed using ELISA. HCV positive cases were confirmed by RT-PCR. Twenty-five patients were positive for the HCV antibody (20.7%); 22 were confirmed positive by PCR. Six patients (5%) were HBsAg-positive. No patients were HIV-positive. Older age were associated with an increased frequency of HCV positive infection (P<0.003). More frequent transfusion, ≥10 times/year, and older age, ≥10years, were reported as predictors of HCV infection (P=0.018 and 0.011, respectively). A significant association of HCV between HBV infections was reported (P value=0.01). There was no significant effect of the pre-transfusion or post-transfusion hemoglobin level on the frequency of HCV positive cases. HCV still represents a major health challenge for frequently transfused Egyptian patients. The prevalence rate of HBV infection remains relatively high. Therefore, it is necessary to implement measures to improve blood transfusion screening.

Serological assays for emerging coronaviruses: challenges and pitfalls

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Serological studies on SARS- and MERS-coronavirus (CoV) diagnostics were reviewed.

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Different types of serological assays and variable antigens were compared.

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Immunogenic epitopes of CoV spike proteins were less conserved than nucleocapsid proteins.

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Use of spike proteins was found to be superior over nucleocapsid proteins.

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Applicability of serological assays for analysis of animal sera was reviewed.

More than a decade after the emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002/2003 the occurrence of a novel CoV termed Middle East respiratory syndrome (MERS) CoV challenges researchers and public health authorities. To control spread and finally contain novel viruses, rapid identification and subsequent isolation of infected individuals and their contacts is of utmost importance. Next to methods for nucleic acid detection, validated serological assays are particularly important as the timeframe for antibody detection is less restricted. During the SARS-CoV epidemic a wide variety of serological diagnostic assays were established using multiple methods as well as different viral antigens. Even though the majority of the developed assays showed high sensitivity and specificity, numerous studies reported on cross-reactive antibodies to antigens from wide-spread common cold associated CoVs. In order to improve preparedness and responsiveness during future outbreaks of novel CoVs, information and problems regarding serological diagnosis that occurred during the SARS-CoV should be acknowledged.

In this review we summarize the performance of different serological assays as well as the applicability of the two main applied antigens (spike and nucleocapsid protein) used during the SARS-CoV outbreak. We highlight challenges and potential pitfalls that occur when dealing with a novel emerging coronavirus like MERS-CoV. In addition we describe problems that might occur when animal sera are tested in serological assays for the identification of putative reservoirs. Finally, we give a recommendation for a serological testing scheme and outline necessary improvements that should be implemented for a better preparedness.

Major risk of blood transfusion in hemolytic anemia patients

Thalassemia is a congenital hemolytic disease caused by defective globin synthesis treated by blood transfusion. Transfusion-transmitted infections still make a great challenge in the management of patients with thalassemia major. The most important worldwide transfusion-transmitted infections are hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV. The objective of this study is to update the prevalence of the three major transfusion-transmitted infections HCV, HBV and HIV among thalassemic patients followed up in the Hematology Department, Children Hospital, Cairo University. The study included 174 multitransfused thalassemic patients (162 major and 12 intermedia), registered at the Pediatric Hematology Clinic, Cairo University. Their age ranged from 2 to 27 years with a mean of 11.26 ± 5.4 years. Patients were subjected to full history taking, stressing on history of blood transfusions (onset, frequency and duration) at a single or multiple centers and abdominal examination. Laboratory investigations including complete blood count, aminotransferases (aspartate aminotransferase and alanine aminotransferase), ferritin and viral markers of HBV surface antigen (HBsAg), HCV antibodies (anti-HCV) and anti-HIV were assayed for all cases by a third-generation ELISA method. HCV PCR was performed for 75 cases. Of the 174 patients, none of them were HBsAg and anti-HIV positive. However, 90 patients were anti-HCV positive (51.7%). HCV PCR was positive in 56 patients (74.3%) of the 75 with positive antibody tested. HCV antibody positivity is statistically significant with age of the patient, serum ferritin and liver transaminases (P < 0.01). HCV-RNA by PCR positivity was significantly related to patients' age and serum ferritin (P < 0.05). Serum ferritin showed statistically significant positive correlation with liver transaminases. Despite the decrease in prevalence of HCV antibody in our patients from 71% in 1995 to 51.7% in our study, yet HCV infection still represents a major health problem for our thalassemic patients, which requires more attention and efforts to challenge. There is a dramatic decrease in the prevalence of HBV infection over the last decade, thanks to mass compulsory vaccination and blood screening. HIV infection does not represent a problem owing to very low population prevalence.

Enzyme-linked immunosorbent assay based on a chimeric antigen bearing antigenic regions of structural proteins Erns and E2 for serodiagnosis of classical swine fever virus infection

The antigenic region (residues 109 to 160) of classical swine fever virus (CSFV) protein E(rns) and the N-terminal antigenic region (residues 1 to 136) of protein E2 were constructed in the form of a fused, chimeric protein, C21E(rns)E2, for use as an enzyme-linked immunosorbent assay (ELISA) antigen for the serodiagnosis of CSFV infection. Tested with 238 negative-field (CSFV-free) sera from Canadian sources, the specificity of the ELISA was determined to be 93.7%. All 20 sera from experimentally infected pigs representing a variety of animals, virus strains, and days postinfection (dpi; range, 7 to 210) were detected as positive (100%). In contrast, an ELISA based on an E(rns) fragment (E(rns)(aa 109-160)) or an E2 fragment (E2(aa 1-221)) identified only 18 (90%) of 20 sera from infected pigs as positive, missing two targets collected at 7 dpi. These data suggest that use of the chimeric antigen C21E(rns)E2 would improve serodiagnostic sensitivity and allow for the detection of CSFV infection as early as 7 dpi.