Original Research

Immune activation is associated with decreased thymic function in asymptomatic, untreated HIV-infected individuals

Thandiwe Manjati, Bongani Nkambule, Hayley Ipp
Southern African Journal of HIV Medicine | Vol 17, No 1 | a445 | DOI: https://doi.org/10.4102/sajhivmed.v17i1.445 | © 2016 Thandiwe Manjati, Bongani Nkambule, Hayley Ipp | This work is licensed under CC Attribution 4.0
Submitted: 10 November 2015 | Published: 28 July 2016

About the author(s)

Thandiwe Manjati, Division of Haematology, Department of Pathology, Stellenbosch University, South Africa; Division of Haematopathology, National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa
Bongani Nkambule, Division of Haematopathology, National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa; Department of Physiology, School of Laboratory and Medical Sciences, University of KwaZulu-Natal, South Africa
Hayley Ipp, Division of Haematology, Department of Pathology, Stellenbosch University, South Africa; Division of Haematopathology, National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa


Share this article

Bookmark and Share

Abstract

Background: Reduced thymic function causes poor immunological reconstitution in human immunodeficiency virus (HIV)-positive patients on combined antiretroviral therapy (cART).The association between immune activation and thymic function in asymptomatic HIV positive treatment-naive individuals has thus far not been investigated.

Aims and objectives: To optimise a five-colour flow cytometric assay for measurement of thymic function by measuring recent thymic emigrants (RTEs) in treatment-naive HIV-infected patients and healthy controls and correlate results with levels of immune activation, CD4 counts and viral load.

Methods: Blood obtained from 53 consenting HIV-positive individuals and 32 controls recruited from HIV prevention and testing clinic in Cape Town, South Africa. RTEs were measured (CD3+/CD4+/CD45RA+/CD31+/CD62L+) and levels were correlated with CD4 counts of HIV-infected individuals, log viral load and levels of immune activation (CD8+/CD38+ T-cells).

Results: HIV-infected individuals had reduced frequencies of RTEs when compared to controls (p = 0.0035). Levels of immune activation were inversely correlated with thymic function(p = 0.0403), and the thymic function in HIV-infected individuals showed no significant correlation with CD4 counts (p = 0.31559) and viral load (p = 0.20628).

Conclusions: There was impaired thymic function in HIV-infected individuals, which was associated with increased levels of immune activation. The thymic dysfunction was not associated with CD4 counts and viral load. Immune activation may result in inflammatory damage to the thymus and subsequent thymic dysfunction, and CD4 counts and viral load may not necessarily reflect thymic dysfunction in HIV.


Keywords

Human immunodeficiency virus (HIV); recent thymic emigrants; immune activation; treatment-naïve; flow cytometry

Metrics

Total abstract views: 1449
Total article views: 2815

 

Crossref Citations

1. HIV as a Cause of Immune Activation and Immunosenescence
T. Sokoya, H. C. Steel, M. Nieuwoudt, T. M. Rossouw
Mediators of Inflammation  vol: 2017  first page: 1  year: 2017  
doi: 10.1155/2017/6825493