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Improving T-cell assays for the diagnosis of latent TB infection: potential of a diagnostic test based on IP-10.

Ruhwald M, Petersen J, Kofoed K, Nakaoka H, Cuevas LE, Lawson L, Squire SB, Eugen-Olsen J, Ravn P - PLoS ONE (2008)

Bottom Line: The IP-10 and IL-2 responses were strongly associated with M.tuberculosis exposure and with grade of infectiousness of the index cases (p<0.0001).IP-10, IL-2, and TST but not QFT-IT was associated with age of the child in the low risk groups (p<0.02).IP-10 is expressed in high levels and results of the IP-10 test were comparable to the QFT-IT.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases 144, Copenhagen University, Hvidovre Hospital, Hvidovre, Denmark. mruhwald@mail.dk

ABSTRACT

Background: There is a need for simple tools such as the M.tuberculosis specific IFN-gamma release assays (IGRA) to improve diagnosis of M.tuberculosis-infection in children. The aim of the study was to evaluate the performance of an IP-10 and IL-2 based tests for the diagnosis of M.tuberculosis-infection in recently exposed children from Nigeria.

Methodology and principal findings: Samples were obtained from 59 children at high risk of infection with M.tuberculosis (contacts of adults with smear and culture-positive tuberculosis) and 61 at low risk (contacts of smear-negative/culture-positive tuberculosis or community controls). IP-10 and IL-2 was measured in plasma after stimulation of whole-blood with M.tuberculosis specific antigens and mitogen. Previously developed criteria for positive IP-10 and IL-2 tests were used and the diagnostic performances of the IP-10 and IL-2 tests were compared with the Quantiferon In-Tube (QFT-IT) and the Tuberculin Skin Tests (TST). In response to M.tuberculosis specific antigens, the high-risk children expressed significantly higher levels of IP-10 (1358 pg/ml[IQR 278-2535 pg/ml]) and IL-2 (164 pg/ml[11-590 pg/ml]) than low risk groups 149 pg/ml(25-497 pg/ml), and 0 pg/ml(0-3 pg/ml), respectively. There was excellent agreement (>89%,k>0.80) between IP-10, IL-2 tests and QFT-IT, better than with TST (>74%,k>0.49). The IP-10 and IL-2 responses were strongly associated with M.tuberculosis exposure and with grade of infectiousness of the index cases (p<0.0001). IP-10, IL-2, and TST but not QFT-IT was associated with age of the child in the low risk groups (p<0.02).

Conclusions/significance: IP-10 is expressed in high levels and results of the IP-10 test were comparable to the QFT-IT. IL-2 was released in low amounts in response to the antigens and not in response to the mitogen therefore IL-2 seems a less useful marker. We have demonstrated that IP-10 and possibly IL-2 could be alternative or adjunct markers to IFN-gamma in the diagnosis infection with M.tuberculosis.

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Related in: MedlinePlus

RD1 antigen dependent biomarker release in children with high and low risk of TB infection.Whole-blood from 59 contacts to a sputum smear-positive household adult (SS+), 38 contacts to a sputum smear-negative culture-positive adult (SS−), and 23 community controls (CC) was stimulated with RD1 antigens. Individual Interferon (IFN)-γ, IFN-γ-inducible protein (IP)-10, and Interleukin (IL)-2, responses after stimulation are shown (the values of the un-stimulated wells have been subtracted). Each dot indicate an individual response, horizontal lines indicate median.
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pone-0002858-g001: RD1 antigen dependent biomarker release in children with high and low risk of TB infection.Whole-blood from 59 contacts to a sputum smear-positive household adult (SS+), 38 contacts to a sputum smear-negative culture-positive adult (SS−), and 23 community controls (CC) was stimulated with RD1 antigens. Individual Interferon (IFN)-γ, IFN-γ-inducible protein (IP)-10, and Interleukin (IL)-2, responses after stimulation are shown (the values of the un-stimulated wells have been subtracted). Each dot indicate an individual response, horizontal lines indicate median.

Mentions: Upon stimulation with Mtb-specific antigens, SS+ contacts released significantly higher concentrations of the three biomarkers than SS− contacts and CC (p<0.0001) did and there was no significant difference between SS− contacts and CC (p>0.4) (table 2 and figure 1). Median levels of IP-10 and IFN-γ after mitogen stimulation were 422 pg/ml (IQR 278–909 pg/ml) and 158 pg/ml (53–532 pg/ml) respectively, whereas the median level of mitogen-induced IL-2 was very low 5 pg/ml (0–254 pg/ml). There were no significant differences in the mitogen-induced levels of IP-10 and IFN-γ between the three groups (p>0.1), but the level of mitogen-induced IL-2 was higher in the SS+ group compared with the low risk groups (p<0.5). In un-stimulated samples, the concentrations of the three biomarkers were low and comparable between the groups (p>0.09).


Improving T-cell assays for the diagnosis of latent TB infection: potential of a diagnostic test based on IP-10.

Ruhwald M, Petersen J, Kofoed K, Nakaoka H, Cuevas LE, Lawson L, Squire SB, Eugen-Olsen J, Ravn P - PLoS ONE (2008)

RD1 antigen dependent biomarker release in children with high and low risk of TB infection.Whole-blood from 59 contacts to a sputum smear-positive household adult (SS+), 38 contacts to a sputum smear-negative culture-positive adult (SS−), and 23 community controls (CC) was stimulated with RD1 antigens. Individual Interferon (IFN)-γ, IFN-γ-inducible protein (IP)-10, and Interleukin (IL)-2, responses after stimulation are shown (the values of the un-stimulated wells have been subtracted). Each dot indicate an individual response, horizontal lines indicate median.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2483344&req=5

pone-0002858-g001: RD1 antigen dependent biomarker release in children with high and low risk of TB infection.Whole-blood from 59 contacts to a sputum smear-positive household adult (SS+), 38 contacts to a sputum smear-negative culture-positive adult (SS−), and 23 community controls (CC) was stimulated with RD1 antigens. Individual Interferon (IFN)-γ, IFN-γ-inducible protein (IP)-10, and Interleukin (IL)-2, responses after stimulation are shown (the values of the un-stimulated wells have been subtracted). Each dot indicate an individual response, horizontal lines indicate median.
Mentions: Upon stimulation with Mtb-specific antigens, SS+ contacts released significantly higher concentrations of the three biomarkers than SS− contacts and CC (p<0.0001) did and there was no significant difference between SS− contacts and CC (p>0.4) (table 2 and figure 1). Median levels of IP-10 and IFN-γ after mitogen stimulation were 422 pg/ml (IQR 278–909 pg/ml) and 158 pg/ml (53–532 pg/ml) respectively, whereas the median level of mitogen-induced IL-2 was very low 5 pg/ml (0–254 pg/ml). There were no significant differences in the mitogen-induced levels of IP-10 and IFN-γ between the three groups (p>0.1), but the level of mitogen-induced IL-2 was higher in the SS+ group compared with the low risk groups (p<0.5). In un-stimulated samples, the concentrations of the three biomarkers were low and comparable between the groups (p>0.09).

Bottom Line: The IP-10 and IL-2 responses were strongly associated with M.tuberculosis exposure and with grade of infectiousness of the index cases (p<0.0001).IP-10, IL-2, and TST but not QFT-IT was associated with age of the child in the low risk groups (p<0.02).IP-10 is expressed in high levels and results of the IP-10 test were comparable to the QFT-IT.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases 144, Copenhagen University, Hvidovre Hospital, Hvidovre, Denmark. mruhwald@mail.dk

ABSTRACT

Background: There is a need for simple tools such as the M.tuberculosis specific IFN-gamma release assays (IGRA) to improve diagnosis of M.tuberculosis-infection in children. The aim of the study was to evaluate the performance of an IP-10 and IL-2 based tests for the diagnosis of M.tuberculosis-infection in recently exposed children from Nigeria.

Methodology and principal findings: Samples were obtained from 59 children at high risk of infection with M.tuberculosis (contacts of adults with smear and culture-positive tuberculosis) and 61 at low risk (contacts of smear-negative/culture-positive tuberculosis or community controls). IP-10 and IL-2 was measured in plasma after stimulation of whole-blood with M.tuberculosis specific antigens and mitogen. Previously developed criteria for positive IP-10 and IL-2 tests were used and the diagnostic performances of the IP-10 and IL-2 tests were compared with the Quantiferon In-Tube (QFT-IT) and the Tuberculin Skin Tests (TST). In response to M.tuberculosis specific antigens, the high-risk children expressed significantly higher levels of IP-10 (1358 pg/ml[IQR 278-2535 pg/ml]) and IL-2 (164 pg/ml[11-590 pg/ml]) than low risk groups 149 pg/ml(25-497 pg/ml), and 0 pg/ml(0-3 pg/ml), respectively. There was excellent agreement (>89%,k>0.80) between IP-10, IL-2 tests and QFT-IT, better than with TST (>74%,k>0.49). The IP-10 and IL-2 responses were strongly associated with M.tuberculosis exposure and with grade of infectiousness of the index cases (p<0.0001). IP-10, IL-2, and TST but not QFT-IT was associated with age of the child in the low risk groups (p<0.02).

Conclusions/significance: IP-10 is expressed in high levels and results of the IP-10 test were comparable to the QFT-IT. IL-2 was released in low amounts in response to the antigens and not in response to the mitogen therefore IL-2 seems a less useful marker. We have demonstrated that IP-10 and possibly IL-2 could be alternative or adjunct markers to IFN-gamma in the diagnosis infection with M.tuberculosis.

Show MeSH
Related in: MedlinePlus