Cryptococcosis-Associated Immune Reconstitution Inflammatory Syndrome Is Associated with Dysregulation of IL-7/IL-7 Receptor Signaling Pathway in T Cells and Monocyte Activation

Ngomu Akeem Akilimali, Daniel M. Muema, Charles Specht, Christina C. Chang, Mahomed Yunus S. Moosa, Stuart M. Levitz, Sharon R. Lewin, Martyn A. French, Thumbi Ndung'U

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8 Scopus citations


Background:Systemic levels of interleukin (IL)-7 at antiretroviral therapy (ART) initiation have previously been shown to be predictive of HIV-linked paradoxical cryptococcosis-associated immune reconstitution inflammatory syndrome (C-IRIS). We therefore explored IL-7/IL-7 receptor (IL-7/IL-7R) signaling pathway dysfunction, with related alterations in immune function, as a mechanism underlying C-IRIS.Method:HIV-infected patients with cryptococcal meningitis who experienced C-IRIS (n = 27) were compared with CD4+ T-cell count-matched counterparts without C-IRIS (n = 27), after antifungal therapy and pre-ART initiation. Flow cytometry was used to assess T-cell and monocyte phenotypes and functions.Results:Proportions of IL-7R+ CD4+ or CD8+ T cells correlated positively with CD4+ T-cell counts and proportions of central memory and naive CD4+ and CD8+ T-cell pre-ART (all r > 0.50 and P < 0.05); however, the former negatively correlated with CD4+ T-cell counts fold-increase on ART in non-C-IRIS but not C-IRIS patients. Higher frequencies of activated monocytes (CD14+CD86+ or CD14+HLA-DR+; P ≤ 0.038) were also observed in C-IRIS compared with non-C-IRIS patients, and those who failed to clear cryptococci from cerebrospinal fluid before ART had higher levels of activated monocytes (CD14+HLA-DR+, P = 0.017) compared with those who cleared. In multivariate regression, CD14+HLA-DR+ monocytes were independently associated with C-IRIS [hazard ratio = 1.055 (1.013-1.098); P = 0.009].Conclusion:In contrast to non-C-IRIS patients, C-IRIS patients displayed a lack of association between proportions of IL-7R+ T cells and several markers of T-cell homeostasis. They also exhibited higher monocyte activation linked to cerebrospinal fluid cryptococcal culture positivity before ART. These data suggest a role for IL-7/IL-7R signaling pathway dysregulation in the pathogenesis of C-IRIS, possibly linked to monocyte activation and residual pathogen burden before ART.

Original languageEnglish
Pages (from-to)596-604
Number of pages9
JournalJournal of Acquired Immune Deficiency Syndromes
Issue number5
StatePublished - 15 Apr 2019
Externally publishedYes


  • AIDS-induced cryptococcal meningitis
  • IL-7/IL-7 receptor signaling pathway
  • T cells
  • antigen-specific responses and immune activation
  • cryptococcosis-associated immune reconstitution inflammatory syndrome
  • monocytes


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