Chikungunya virus RNA and antibody testing at a National Reference Laboratory since the emergence of Chikungunya virus in the Americas.

Since first reported in the Americas in December 2013, chikungunya virus (CHIKV) infections have been documented in travelers returning from the Caribbean, with many cases identified by CHIKV antibody and/or RNA testing at our laboratory. We used our large data set to characterize the relationship between antibody titers and RNA detection and to estimate IgM persistence. CHIKV RNA was measured by nucleic acid amplification and CHIKV IgG/IgM by indirect immunofluorescence.

Estimation of dengue virus IgM persistence using regression analysis.

Dengue virus IgM persistence was estimated using follow-up sera from 98 patients (60 with primary infections and 38 with secondary infections) whose first-specimen IgM index was strongly positive, suggesting recent disease onset. Regression analysis of the follow-up IgM index versus days between samples yielded a trend line that reached the cut-point index (1.10) at 179 days for the primary infection group and 139 days for the secondary infection group.

Dengue virus immunoglobulin M detection in a reference laboratory setting during the 2010 dengue virus outbreak on Caribbean islands.

A large outbreak of dengue virus (DV) infections occurred on Caribbean islands during 2010, with cases peaking during the second half of the year. In conjunction with the outbreak, we observed an unprecedented spike in the number of sera submitted for DV antibody testing between June and December 2010, with a concomitant increase in the number of IgM-positive specimens, indicative of acute DV infection. Analysis of the place of residence of the IgM-positive patients identified from June to December of 2010 revealed that 58.

Evaluation of a multiplex bead-based screening assay for detection of binding antibodies to interferon-beta.

Multiple sclerosis patients treated with interferon-beta (IFNbeta) can develop neutralizing binding antibodies (BAbs) that reduce the agent's effectiveness. Screening for these antibodies can be performed by ELISA. We investigated a multianalyte immune detection (MAID) assay as an alternative to ELISA to detect anti-IFNbeta-1a and -1b.

Virus and antibody dynamics in acute west nile virus infection.

Background: The dynamics of the early stages of West Nile virus (WNV) infection can be assessed by follow-up studies of viremic blood donors.

Methods: A total of 245 donors with WNV viremia were followed up weekly for 4 weeks and then monthly for up to 6 additional months or until seroconversion. Plasma samples were tested for WNV RNA by transcription-mediated amplification (TMA) and for WNV-specific IgM and IgG antibodies.