Comparison of commercial methods of immunoblot, ELISA, and chemiluminescent immunoassay for detecting type-specific herpes simplex viruses-1 and -2 IgG.

BACKGROUND: Serology for type-specific herpes simplex virus (HSV) is based on the use of the respective glycoprotein G (gG). METHODS: Chemiluminescent immunoassay (CLIA; BIO-FLASH® , Biokit, Spain), ELISA (HerpeSelect® , Focus, USA), and immunoblot (IB; Virotech, Germany) for detecting HSV-1- and HSV-2-specific IgG were compared using 384 serum samples received for HSV serology. The samples were classified as positive or negative according to a consensus criterion. RESULTS: For HSV-1, 262 samples were positive and 118 were negative (four samples were unclassifiable). IB showed agreement, sensitivity, and specificity values of 98.68%, 98.47% and 99.15%, respectively. The corresponding figures for CLIA and ELISA were 98.95%, 99.24% and 98.31%, and 98.16%, 99.62% and 94.92%, respectively. For HSV-2, 106 samples were positive and 278 were negative. Agreement, sensitivity, and specificity of IB were 99.48%, 98.11%, and 100%, respectively. The corresponding figures for CLIA and ELISA were 99.48%, 99.06% and 99.64%, and 98.18%, 99.06% and 97.84%, respectively. CONCLUSION: The three methods showed excellent and equivalent performance characteristics for the detection of type-specific IgG to HSV-1 and HSV-2.

Evaluación del sistema VIDAS para estudio de marcadores serológicos de infección por el virus Epstein Barr / Performance of the VIDAS automated immunoassay for the determination of Epstein-Barr virus serological status

Se han evaluado ensayos de fluorescencia ligada a enzima (VIDAS EBV VCA IgM, VIDAS EBV VCA/EA IgG y VIDAS EBV EBNA IgG (Biomérieux, Francia) para la determinación de marcadores de infección por el virus Epstein Barr, así como para el establecimiento de perfiles de anticuerpos, comparándolos con ensayos de inmunofluorescencia como referencia. Los ensayos evaluados han mostrado buenas características de sensibilidad, especificidad y coincidencia porcentual de resultados, lo que les hace adecuados para su aplicación en laboratorios de diagnóstico clínico (AU)

Enzyme linked fluorescent assays (VIDAS EBV VCA IgM, VIDAS EBV VCA/EA IgG and VIDAS EBV EBNA IgG (Biomérieux, France) were evaluated to determine markers for infection of Epstein Barr virus, as well as to establish antibody profiles, compared with immunofluorescence assays as reference. The assays evaluated showed good values for sensitivity, specificity and agreement, making them useful for their application in clinical laboratories (AU)

[Performance of the VIDAS automated immunoassay for the determination of Epstein-Barr virus serological status]. / Evaluación del sistema VIDAS para estudio de marcadores serológicos de infección por el virus Epstein Barr.

Enzyme linked fluorescent assays (VIDAS EBV VCA IgM, VIDAS EBV VCA/EA IgG and VIDAS EBV EBNA IgG (Biomérieux, France) were evaluated to determine markers for infection of Epstein Barr virus, as well as to establish antibody profiles, compared with immunofluorescence assays as reference. The assays evaluated showed good values for sensitivity, specificity and agreement, making them useful for their application in clinical laboratories.

Evaluation of four commercial systems for the diagnosis of Epstein-Barr virus primary infections.

To compare the performance of four diagnostic commercial systems for Epstein-Barr virus (EBV) serology (for IgM and IgG virus capsid antigen [VCA] and EBV nuclear antigen [EBNA] antibodies), a collection of 125 samples from clinically suspected infectious mononucleosis cases was studied. Indirect immunofluorescence (IIF) for VCA IgM and IgG antibodies and anticomplement immunofluorescence for EBNA antibodies (Meridian Bioscience Inc.) were used as reference methods. By these methods, the cases were classified EBV primary infection (presence of IgM to VCA or IgG to VCA in the absence of EBNA antibodies; n = 82), EBV past infection (presence of VCA IgG and EBNA antibodies in the absence of VCA IgM; n = 26), or no infection (negative for the three markers; n = 17). The following systems were tested: two chemiluminescent immunoassays (CLIAs; the Liason [CLIA-L; DiaSorin] and the Immulite 2000 [CLIA-I; Siemens]), immunofiltration (IF; All.Diag), and an enzyme-linked immunosorbent assay (ELISA; DiaSorin). In the IgM assays, sensitivities ranged from 67.1% (ELISA) to 92.2% (CLIA-L) and specificities ranged from 93.8% (CLIA-L) to 100% (IF). In the VCA IgG assays, sensitivities varied from 79.4% (IF) to 94.4% (CLIA-I) and specificities varied from 94.4% (IF and CLIA-L) to 100% (CLIA-I and ELISA). In EBNA assays, sensitivities ranged from 78.1% (IF) to 93.8% (CLIA-I) and specificities ranged from 32.3% (CLIA-L) to 91.4% (IF). In relation to EBV profiles, the corresponding figures for sensitivity (in detecting primary infection) for IF, CLIA-L, CLIA-I, and ELISA were 92.7%, 93.8%, 89%, and 89.6%, respectively, and those for specificity (to exclude primary recent infection) were 90.7%, 94.6%, 97.7%, and 95.2%, respectively. Although there were limitations in some individual markers, especially CLIA-L for EBNA IgG, the systems evaluated appear to be useful for diagnosis of EBV infection.

Comparison of IgG avidity assays in the confirmation of the diagnosis of cytomegalovirus primary infection.

We have compared three ELISA techniques and one chemiluminescence immunoassay technique for determining cytomegalovirus (CMV) immunoglobulin G (IgG) avidity in serum samples from patients with recent and past CMV infections. Sensitivity varied from 84.6% to 100%; and specificity from 78.6% to 100%. IgG avidity assays appear to be adequate additional tools for characterizing CMV infections.

Detection of Chlamydophila pneumoniae IgG in paired serum samples: comparison of serological techniques in pneumonia cases.

Serological diagnosis of Chamydophila pneumoniae is usually undertaken by complement fixation test (CFT) or by microimmunofluorescence (MIF). A number of commercial methods for detecting C. pneumoniae-specific IgG have been developed. The aim of this study was to compare the performance characteristics of six methods for the diagnosis of pneumonia due to C. pneumoniae, including CFT (in house), MIF (Vircell, Spain), and four ELISAs (Medac, Germany; Savyon, Israel; Serion, Germany; and DRG, Germany). ELISA-Medac, ELISA-Savyon, ELISA-DRG and MIF use C. pneumoniae antigens while ELISA-Serion and CFT use Chlamydophila genus-specific antigen. Acute and convalescent samples from 85 pneumonia patients were studied. Using CFT, cases were initially classified as due to Chlamydophila (43 cases); to other agents (23 cases) (influenza A and B, Mycoplasma pneumoniae, respiratory syncytial virus, adenovirus and Legionella pneumophila); or as negative (19 cases). Cases were considered positive if they showed seroconversion, a significant rise in titer or high titer; and were finally classified as positive if they gave a positive result in at least three assays. Sensitivity values ranged from 87% to 97.8%; and specificity from 84.6% to 97.4%. In conclusion, the assays compared appear to be useful tools for the diagnosis of pneumonia due to Chlamydophila.

[Comparison of serological procedures used for the diagnosis of viral exanthema in laboratories participating in the measles elimination plan]. / Comparación de los procedimientos serológicos de los laboratorios del Plan para la Eliminación del Sarampión en el diagnóstico de exantemas víricos.

OBJECTIVE: The comparison of serological methods used by the laboratories participating in the Network for the Elimination of Measles to diagnose measles virus infection as well as differential diagnosis with other exanthematic diseases are compared. MATERIALS AND METHODS: One panel of 20 serum samples including measles (12), rubella (4), parvovirus B19 (2) and dengue (2) infections was established. All cases were diagnosed by detection of specific IgM. The panel was sent to the laboratories of the Network. The results were compared with those obtained at the reference laboratory. RESULTS AND DISCUSSION: Regarding measles, IgM response from 20 laboratories (19 by ELISA and 1 by indirect immunofluorescence) was obtained, with an agreement of 91.5%. Related to rubella IgM, replay from 6 laboratories, using ELISA, was received, with an agreement of 98.7%. With respect to parvovirus B19 IgM, response from 10 laboratories (8 by ELISA and 2 by indirect immunofluorescence) was obtained, with an agreement of 94.6%. Results about dengue virus were not reported by any laboratory. CONCLUSION: Some laboratories from the network should review the methods used for the diagnosis of measles and other exanthematic diseases. The results reassert the need for a reference laboratory to support confirmation of the results.

Comparación de los procedimientos serológicos de los laboratorios del Plan para la Eliminación del Sarampión en el diagnóstico de exantemas víricos / Comparison of serological procedures used for the diagnosis of viral exanthema in laboratories participating in the measles elimination plan

OBJETIVO. Comparar los métodos serológicos empleados por los laboratorios de la Red del Plan de Eliminación del Sarampión para el diagnóstico de la infección por virus del sarampión, y para el diagnóstico diferencial con otras enfermedades exantemáticas. MATERIALES Y MÉTODOS. Se ha establecido un panel de 20 muestras de suero de casos de enfermedad exantemática (sarampión [12], rubéola [4], parvovirus B19 [2] y dengue [2]), diagnosticados por detección de inmunoglobulina M (IgM) específica. El panel se ha enviado a los laboratorios de la Red. RESULTADOS Y DISCUSIÓN. Se han recibido respuestas de 20 laboratorios para IgM frente a sarampión, 19 realizadas por enzimoinmunoanálisis (ELISA) y una por inmunofluorescencia indirecta (IFI). La concordancia con el laboratorio de referencia ha sido del 91,5 por ciento. Para IgM de rubéola se han recibido respuestas de seis laboratorios (todas obtenidas por ELISA) con una concordancia del 98,7 por ciento. Para IgM de parvovirus B19 se ha recibido respuesta de 10 laboratorios (ocho realizaron ELISA y dos IFI), con una concordancia del 94,6 por ciento. Ningún laboratorio realizó diagnóstico de dengue. CONCLUSIÓN. Algunos de los laboratorios de la Red deberían revisar los métodos empleados para el diagnóstico de sarampión. Por otra parte, se considera necesaria la existencia de un laboratorio de referencia que sirva de apoyo para la confirmación de resultados, así como para el diagnóstico de otros agentes exantemáticos, cuando los antecedentes epidemiológicos así lo requieran (AU)

Acute meningitis due to Toscana virus infection among patients from both the Spanish Mediterranean region and the region of Madrid.

Toscana virus (TOSV) is a member of the genus Phlebovirus that is transmitted to humans by two different species of sand fly and causes acute aseptic meningitis (AAM) and meningoencephalitis in Central Italy. Fifteen cases of AAM due to TOSV have been found at the Spanish province of Granada, but no data regarding the presence of TOSV-related disease in other regions of Spain have been still reported. A collection of 88 serum and 53 cerebrospinal fluid (CSF) samples taken from 81 selected patients with AAM of unknown aetiology, residing at Madrid or at the southern Mediterranean coast of Spain, was retrospectively studied for presence of TOSV-specific antibodies from both IgG and IgM classes. Anti-TOSV IgG was also investigated in 457 serum samples from healthy individuals, aged 2-60 years, residing at the south of the Region of Madrid. Specific IgM in serum and/or intrathecally produced anti-TOSV IgG were detected in seven patients, three residents from the Mediterranean region and the remainder four from the Region of Madrid. The overall prevalence of anti-TOSV among the healthy population studied was 5%. These results confirm the role of TOSV as an agent causing AAM in the Spanish Mediterranean coast, extend these findings to the central region of the country and suggest that TOSV might be producing infection and neurological disease in every area of Spain harbouring significant populations of the viral vectors.