Combinatorial Immunoprofiling in Latent Tuberculosis Infection. Toward Better Risk Stratification

Abstract

Rationale: Most immunocompetent patients diagnosed with latent tuberculosis infection (LTBI) will not progress to tuberculosis (TB) reactivation. However, current diagnostic tools cannot reliably distinguish nonprogressing from progressing patients a priori, and thus LTBI therapy must be prescribed with suboptimal patient specificity. We hypothesized that LTBI diagnostics could be improved by generating immunomarker profiles capable of categorizing distinct patient subsets by a combinatorial immunoassay approach.Objectives: A combinatorial immunoassay analysis was applied to identify potential immunomarker combinations that distinguish among unexposed subjects, untreated patients with LTBI, and treated patients with LTBI and to differentiate risk of reactivation.Methods: IFN-g release assay (IGRA) was combined with a flow cytometric assay that detects induction of CD25 1 CD134 1 coexpression on TB antigen-stimulated T cells from peripheral blood. The combinatorial immunoassay analysis was based on receiver operating characteristic curves, technical cut-offs, 95% bivariate normal density ellipse prediction, and statistical analysis. Risk of reactivation was estimated with a prediction formula.Measurements and Main Results: Sixty-five out of 150 subjects were included. The combinatorial immunoassay approach identified at least four different T-cell subsets. The representation of these immune phenotypes was more heterogeneous in untreated patients with LTBI than in treated patients with LTBI or unexposed groups. Patients with IGRA(1) CD41 CD25 1 CD134 1 T-cell phenotypes had the highest estimated reactivation risk (4.11 6 2.11%).Conclusions: These findings suggest that immune phenotypes defined by combinatorial assays may potentially have a role in identifying those at risk of developing TB; this potential role is supported by risk of reactivation modeling. Prospective studies will be needed to test this novel approach.

Flow cytometric immune profiling in infliximab-associated tuberculosis

“…[9][10][11] Combinatorial interferon gamma release assays and FC assays assessing TB antigen-induced T-cell CD25 (interleukin-2 receptor α chain) and CD134 (TNF-α receptor superfamily member) co-expression were recently described as a method to risk stratify patients with LTBI. 7 Furthermore, this strategy has been used to identify patients with LTBI with HIV co-infection. 12 However, FC has not been used to clinically identify active TB, and the effects of TNFA on the FC detection of CD134 have not been described.…”

“…Detailed methods have been reported previously. 7 CD25 + CD134 + co-expression was detected on 0.34% and 0.84% of RD1 peptide and PPD-stimulated CD3 + CD4 + T cells, respectively (Figure 2). In addition, upregulation of CD25 + CD134 + was present on 0.26% and 0.59% of RD1 peptide and PPD-stimulated CD3 + CD8 + T cells, respectively.…”

Comment on “A Cytokine-Independent Approach To Identify Antigen-Specific Human Germinal Center T Follicular Helper Cells and Rare Antigen-Specific CD4+ T Cells in Blood”

“…The results are the most robust to date for identification of Ag-specific GC Tfh cells in humans (2) and non-human primates (1). We then noted, and cited, that Zaunders and colleagues (5, 6) previously determined that upregulation of OX40 and CD25 could be used as activation markers to identify Ag-specific CD4 T cells in whole anti-coagulated blood, and that approach had been used in additional studies (7,8). We therefore examined whether using CD25, OX40, and/or PD-L1 could be successfully applied for identification of Ag-specific CD4 T cells in blood for our Ags of interest, which would allow for quantitation of Agspecific GC Tfh cells and non-Tfh cells using the same experimental technique.…”

“…Levings, unpublished data) providing a simple and robust method to obtain viable Ag-specific cell populations for functional analysis even when present at low levels (2,7,8). Furthermore, the frequency and phenotype of these responses have been associated with the effectiveness of immune responses and response to therapy in several diseases (7, 10, 11).…”

Update in Tuberculosis/Pulmonary Infections 2015

“…1 T cell coexpression of CD25 and CD134 could identify immunologic profiles of individuals who may be at increased risk of developing active TB (11). A similar approach combining the QGIT, TST, and cytokine profiles was assessed by Tebruegge and colleagues looking at 149 children with possible TB (12).…”