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Ex vivo profiling of cytokines/chemokines in patients with tuberculosis and latent tuberculosis infection

Abstract number: 1732_211

Bodmer T., Grandgirard D., Bigler S., Daubenberger C., Leib S.

Objectives: While in most cases infection with Mycobacterium tuberculosis (Mtb) is contained (latent Mtb infection; LTBI), it progresses to overt disease (TB) in a small proportion of those infected. We studied the cytokine/chemokine profiles associated with LTBI and TB in order to gain insight into ongoing immune activation events in Mtb-infection.

Methods: Blood was obtained from patients with culture-confirmed TB (n = 4), with recently acquired LTBI (n = 3), and from healthcare workers without Mtb exposure (n = 6). Interferon-gamma (IFN-g) that was released from sensitised lymphocytes upon ex vivo stimulation with Mtb-specific antigens was determined using the QuantiFERON-TB® Gold In Tube assay as recommended by the manufacturer (Cellestis Ltd., Carnegie, Australia). Microsphere-based multiplex assays (Lincoplex®, Linco Research Inc., St Charles, MA, USA) were used to assess the plasma concentrations of IFN-g, TNF-a, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p40, IL-12p70 IL-13, IL-15, Fraktalkine, GM-CSF, MCP-1, and IP-10 before (NIL) and after (TbAg) ex vivo stimulation. Values were determined using Bio-Plex Manager (Bio-Rad Laboratories, Hercules, CA, USA). The limit of detection was 3.2 pg/mL. Statistical analysis was performed using Prism 4.1 (GraphPad Software Inc., San Diego, CA, USA). The Kruskal-Wallis test was used for multiple group comparison, and the Mann-Whitney test for group to group comparison.

Results: IFN-g, IP-10, IL-2, GM-CSF, IL-13 concentrations were significantly higher in patients with TB and LTBI as compared to controls (Table).

 DTb Ag–NIL, median (range), pg/mL]ANOVAMann–Whitney
ControlTBLTBIKruskal-WallisControl vs TBControl vs LTBI 
IFN-g-0.2 [-3.0–2.0]175.3 [131.0–238.6]115.9 [2.2–185.4]P < 0.02P < 0.03P < 0.03
IP-10212.0 [126.0–1409]18,188 [3,806–46,279]12,996 [1,809–24,112]P < 0.02P < 0.01P < 0.03
IL-20.47 [-4.6–59.9]630.5 [404.5–5,871]413.5 [280.1–887.5]P < 0.02P < 0.01P < 0.03
GM-CSF-2.3 [-12.9–11.0]27.6 [2.9–481.2]20.8 [16.6–59.1]P < 0.02P < 0.02P < 0.03
IL-13-2.8 [-34.6–14.2]61.6 [0.2–144.2]57.6 [2.9–59.5]P < 0.04P < 0.04P < 0.05

Conclusions: Mean plasma concentrations of IP-10 were 50 to 90-fold higher than those of IFN-g, both in patients with active TB and LTBI. Assessment of IP-10 might substantially increase the sensitivity of IFN-g release assays (IGRA) for detecting Mtb infection. Ex vivo profiling of cytokines/chemokines using IGRA in combination with flow-cytometer multiplex assays identified additional candidate parameters to confirm Mtb infection and will improve our understanding of TB pathogenesis.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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