STUDY OF ELISA TEST-SYSTEMS OF DIFFERENT FORMATS FOR DETECTION OF MEASLES VIRUS SPECIFIC IgM IN DIFFERENT GEOGRAPHIC ZONES

Abstract

Detection of the measles virus (MV) specific IgM antibodies in blood serum of patients is considered to be the main standard for the laboratory confirmation of measles diagnosis, the test being acknowledged by WHO. As it was demonstrated earlier the specific IgM antibodies as the marker of the acute MV infection were detected in 97.2–100% of blood serum samples from patients using the ELISA test-systems of the “capture” format (Microimmun Ltd. and Vector Best). In case when the ELISA test-system of the “indirect” format (Siemens, Germany) was used only 63.9% of these sera turned to be IgM positive. And on the contrary using the “indirect” format ELISA test-system Euroimmun, Germany, for detection of the MV specific IgM the false positive results were obtained.The aim of the study was the comparative evaluation of the different format ELISA test-systems used for the detection of the MV specific IgM antibodies in blood sera of patients and healthy adults collected in different geographic zones.Materials and methods. In total 108 serum specimens collected in 2015–2017 were studied: from healthy adult Guineans, residents of the Republic of Guinea (RG); patients aged 1–70 with the initial “infectious mononucleosis”, “infectious cytomegalovirus” and “rubella” diagnosis and taken from the bank of sera in the Subnational Measles/Rubella laboratory, StP Measles/Rubella RC in NWFR. The MV specific IgM antibodies were detected using the commercial ELISA test-systems “VectoMeasles-IgM” (Vector-Best, Russia) (“capture” format) and “Anti-Measles Virus ELISA IgM (NP)” (Euroimmun Medizinische Labordiagnostik AG, Germany) («indirect» format). The specific Epshtein-Barr Virus (EBV) IgM and IgG antibodies were detected with the commercial ELISA test-systems «DS-ELISA-anti-EBV-VCA-M», «DS-ELISA-anti-EBV-EA-G» and «DS-ELISA-anti-EBV-NA-G» (“Diagnostic Systems”, Russia).Results and discussion. The MV specific IgM antibodies were not revealed in the total of 108 blood serum samples from the healthy adults and patients, residents of the Russia and of the RG, with the “capture” format “VectoMeasles-IgM” ELISA test-system. The absence of the acute MV infection was also confirmed by the high measles immunity level (i.e. IgG MV antibodies titers) as well as by detection of the IgG antibodies of high avidity. At the same time in 6 of 108 total sera (5.5%) IgM MV antibodies were detected with the «indirect» format ELISA test system Euroimmun, Germany. In these 6 sera the EBV specific antibodies were also evidenced. The results obtained demonstrate the nonspecific reaction due to the possible reactivity with anti-EBV antibodies. Besides this the different percentage of the false positive reactions in sera from healthy adults, residents of the RG and residents of Russia was determined — 8.5±4.0% and 3.2±2.2% correspondently. Thus the preliminary results, and to get the final results for general conclusions increase of the total amount of the clinical specimens under studying is of extremely importance.