1. Application of Flow Cytometry in the Diagnostics Pipeline of Primary Immunodeficiencies Underlying Disseminated Talaromyces marneffei Infection in HIV-Negative Children.
- Author
-
Lee PP, Lao-Araya M, Yang J, Chan KW, Ma H, Pei LC, Kui L, Mao H, Yang W, Zhao X, Trakultivakorn M, and Lau YL
- Subjects
- Adolescent, Adult, CD40 Ligand immunology, CD40 Ligand metabolism, Child, Child, Preschool, Female, Humans, Infant, Lymphocyte Count, Male, Mycoses diagnosis, Mycoses microbiology, Primary Immunodeficiency Diseases diagnosis, Primary Immunodeficiency Diseases microbiology, STAT1 Transcription Factor immunology, STAT1 Transcription Factor metabolism, Sensitivity and Specificity, Talaromyces physiology, Flow Cytometry methods, Immunoglobulin Isotypes immunology, Mycoses immunology, Primary Immunodeficiency Diseases immunology, Talaromyces immunology
- Abstract
Talaromyces (Penicillium) marneffei is an AIDS-defining infection in Southeast Asia and is associated with high mortality. It is rare in non-immunosuppressed individuals, especially children. Little is known about host immune response and genetic susceptibility to this endemic fungus. Genetic defects in the interferon-gamma (IFN-γ)/STAT1 signaling pathway, CD40/CD40 ligand- and IL12/IL12-receptor-mediated crosstalk between phagocytes and T-cells, and STAT3-mediated Th17 differentiation have been reported in HIV-negative children with talaromycosis and other endemic mycoses such as histoplasmosis, coccidioidomycosis, and paracoccidioidomycosis. There is a need to design a diagnostic algorithm to evaluate such patients. In this article, we review a cohort of pediatric patients with disseminated talaromycosis referred to the Asian Primary Immunodeficiency Network for genetic diagnosis of PID. Using these illustrative cases, we propose a diagnostics pipeline that begins with immunoglobulin pattern (IgG, IgA, IgM, and IgE) and enumeration of lymphocyte subpopulations (T-, B-, and NK-cells). The former could provide clues for hyper-IgM syndrome and hyper-IgE syndrome. Flow cytometric evaluation of CD40L expression should be performed for patients suspected to have X-linked hyper-IgM syndrome. Defects in interferon-mediated JAK-STAT signaling are evaluated by STAT1 phosphorylation studies by flow cytometry. STAT1 hyperphosphorylation in response to IFN-α or IFN-γ and delayed dephosphorylation is diagnostic for gain-of-function STAT1 disorder, while absent STAT1 phosphorylation in response to IFN-γ but normal response to IFN-α is suggestive of IFN-γ receptor deficiency. This simple and rapid diagnostic algorithm will be useful in guiding genetic studies for patients with disseminated talaromycosis requiring immunological investigations., (Copyright © 2019 Lee, Lao-araya, Yang, Chan, Ma, Pei, Kui, Mao, Yang, Zhao, Trakultivakorn and Lau.)
- Published
- 2019
- Full Text
- View/download PDF