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Infection with Zika virus (ZIKV), a member of the Flavivirus genus of the Flaviviridae family, typically results in mild self-limited illness, but severe neurological disease occurs in a limited subset of patients. In contrast, serious outcomes commonly occur in pregnancy that affect the developing fetus, including microcephaly and other major birth defects. The genetic similarity of ZIKV to other widespread flaviviruses, such as dengue virus (DENV), presents a challenge to the development of specific ZIKV diagnostic assays. Nonstructural protein 1 (NS1) is established for use in immunodiagnostic assays for flaviviruses. To address the cross-reactivity of ZIKV NS1 with proteins from other flaviviruses we used site-directed mutagenesis to modified putative epitopes. Goat polyclonal antibodies to variant ZIKV NS1 were affinity-purified to remove antibodies binding to the closely related NS1 protein of DENV. An antigen-capture ELISA configured with the affinity-purified polyclonal antibody showed a linear dynamic range between approximately 500 to 30 ng/mL, with a limit of detection of between 1.95 and 7.8 ng/mL. NS1 proteins from DENV, yellow fever virus, St. Louis encephalitis virus and West Nile virus showed significantly reduced reactivity in the ZIKV antigen-capture ELISA. Refinement of approaches similar to those employed here could lead to development of ZIKV-specific immunoassays suitable for use in areas where infections with related flaviviruses are common.

Accessibility to immunohistochemistry (IHC) is invaluable to proper diagnosis and treatment of pediatric patients with malignant neoplasms. Whereas IHC is widely available in anatomic pathology laboratories in high-income countries, access to it in anatomic pathology laboratories of low- and middle-income countries remains a struggle, with many limitations. To advance the quality of the pathology service offered to children with cancer in areas with limited resources, a 5-day pathology training workshop was offered to pathologists and histotechnologists from various countries of the Central American and Caribbean region. An initial assessment of the workshop participants’ current laboratory capacities was performed, and a regional training center was selected. Didactic and hands-on activities were offered, and review and evaluation of the IHC slides produced during the training course were compared with original slides from the participants’ sites. This model of intensive 5-day training appears to be effective and can potentially be used in other budget-constrained regions. Moreover, it can serve as a continuing education activity for pathologists and histotechnologists, and as part of validations and quality improvement projects to build capacity and develop IHC assay proficiency in low- and middle-income countries.

The Epstein-Barr virus (EBV)-encoded latent membrane proteins (LMP1 and LMP2) are consistently expressed by malignant Hodgkin Reed-Sternberg (HRS) cells of EBV-associated Hodgkin's disease (HD). The EBV LMP1 has been implicated in tumorogenesis. Cytotoxic T lymphocyte (CTL) responses to both of these proteins have been shown in the blood of EBV-seropositive individuals, and in HD, the apparent failure of the CTL response to eliminate HRS cells expressing LMP1 in vivo has given rise to the suggestion that HD may be characterized by the presence of defects in antigen CTL-presentation or in CTL dysfunction. This study examined 28 cases seen at the Regional Children's Hospital Arturo Grullon in Santiago, the Dominican Republic, by immunohistochemistry. High level of expression of major histocompatibility complex (MHC) class I molecules in HRS cells of EBV-associated HD was recorded. These results suggest that deregulation of MHC class I molecules does not account for the apparent ability of EBV to infect HRS cells and to evade CTL protection. Therefore, the result from our work and similar studies will help to determine whether, or which, immunotherapy should be used in positive and negative cases of HD related to EBV. Microsc. Res. Tech. 68:247–249, 2005. © 2005 Wiley-Liss, Inc.