Abstract

Background. Cerebrospinal fluid (CSF) cryptococcal glucuronoxylomannan antigen (CrAg) titers generally correlate with quantitative fungal culture burden; however, correlation is not precise. Some patients have higher CrAg titers with lower fungal burdens and vice versa. We hypothesized that the relative discordancy between CrAg titer and quantitative culture burden reflects the relative degree of CrAg shedding by Cryptococcus neoformans and is associated with human immune responses.

Methods. One hundred ninety human immunodeficiency virus-infected individuals with cryptococcal meningitis were enrolled in Uganda and South Africa. We compared initial CSF CrAg titers relative to their CSF quantitative cultures to determine low (n = 58), intermediate (n = 68), or high (n = 64) CrAg shedders. We compared cytokines measured by Luminex multiplex assay on cryopreserved CSF and 10-week mortality across shedding groups using linear and logistic regression and distribution of genotypes by multilocus sequence typing.

Results. The relative degree of CrAg shedding was positively associated with increasing CSF levels of the following: interleukin (IL)-6, IL-7, IL-8, and tumor necrosis factor-α (each P < 0.01), which are all secreted by antigen-presenting cells and negatively associated with vascular endothelial growth factor (P = .01). In addition, IL-5, IL-13, granulocyte colony-stimulating factor, and macrophage chemotactic protein were decreased in low-CrAg shedders compared with intermediate shedders (each P ≤ .01). Type 1 T-helper cells (Th1) cytokine responses and 10-week mortality did not differ between the shedding groups. Cryptococcal genotypes were equally distributed across shedding groups.

Conclusions. Discordancy between CrAg shedding and expected shedding based on quantitative fungal burden is associated with detectable immunologic differences in CSF, primarily among secreted cytokines and chemokines produced by antigen-presenting cells and Th2.

Details

Title
Human Immune Response Varies by the Degree of Relative Cryptococcal Antigen Shedding
Author
Boulware, David R 1 ; Maximilian von Hohenberg 2 ; Rolfes, Melissa A 1 ; Bahr, Nathan C 2 ; Rhein, Joshua 3 ; Akampurira, Andrew 4 ; Williams, Darlisha A 3 ; Kabanda Taseera 5 ; Schutz, Charlotte 6 ; McDonald, Tami 7 ; Muzoora, Conrad 5 ; Meintjes, Graeme 6 ; Meya, David B 8 ; Nielsen, Kirsten 7 ; Katherine Huppler Hullsiek 9 

 Division of Infectious Diseases and International Medicine, Department of Medicine; School of Public Health 
 Division of Infectious Diseases and International Medicine, Department of Medicine 
 Division of Infectious Diseases and International Medicine, Department of Medicine; Infectious Disease Institute, Makerere University 
 Makerere University College of Health Sciences, Kampala 
 Mbarara University of Science and Technology, Uganda 
 Infectious Diseases Unit, GF Jooste Hospital; Department of Medicine, Faculty of Health Sciences; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa 
 Department of Microbiology and Immunology, University of Minnesota, Minnesota 
 Division of Infectious Diseases and International Medicine, Department of Medicine; Infectious Disease Institute, Makerere University; Makerere University College of Health Sciences, Kampala 
 School of Public Health 
Publication year
2016
Publication date
Winter 2016
Publisher
Oxford University Press
e-ISSN
23288957
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3171061673
Copyright
© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. This work is published under http://creativecommons.org/licenses/by-nc-nd/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.