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BCG-specific IgG-secreting peripheral plasmablasts as a potential biomarker of active tuberculosis in HIV negative and HIV positive patients.

Ashenafi S, Aderaye G, Zewdie M, Raqib R, Bekele A, Magalhaes I, Lema B, Habtamu M, Rekha RS, Aseffa G, Maeurer M, Aseffa A, Svensson M, Andersson J, Brighenti S - Thorax (2012)

Bottom Line: Immunodiagnosis of TB also included the tuberculin skin test and the interferon (IFN)-γ release assay, QuantiFERON.BCG-specific IgG titres were particularly high among patients coinfected with TB and HIV with CD4 T-cell counts <200 cells/ml who produced low levels of Mycobacterium tuberculosis-specific IFNγ in vitro.Elevated IgG responses were associated with impaired peripheral T-cell responses, including reduced T-cell numbers and low M tuberculosis-specific IFNγ production.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Center for Infectious Medicine (CIM), Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.

ABSTRACT

Background: Diagnosis of active tuberculosis (TB) among sputum-negative cases, patients with HIV infection and extra-pulmonary TB is difficult. In this study, assessment of BCG-specific IgG-secreting peripheral plasmablasts, was used to identify active TB in these high-risk groups.

Methods: Peripheral blood mononuclear cells were isolated from patients with TB and controls and cultured in vitro using an assay called Antibodies in Lymphocyte Supernatant, which measures spontaneous IgG antibody release from migratory plasmablasts. A BCG-specific ELISA and flow cytometry were used to quantify in vivo activated plasmablasts in blood samples from Ethiopian subjects who were HIV negative or HIV positive. Patients diagnosed with different clinical forms of sputum-negative active TB or other diseases (n=96) were compared with asymptomatic individuals including latent TB and non-TB controls (n=85). Immunodiagnosis of TB also included the tuberculin skin test and the interferon (IFN)-γ release assay, QuantiFERON.

Results: This study demonstrated that circulating IgG+ plasmablasts and spontaneous secretion of BCG-specific IgG antibodies were significantly higher in patients with active TB compared with latent TB cases and non-TB controls. BCG-specific IgG titres were particularly high among patients coinfected with TB and HIV with CD4 T-cell counts <200 cells/ml who produced low levels of Mycobacterium tuberculosis-specific IFNγ in vitro.

Conclusions: These results suggest that BCG-specific IgG-secreting peripheral plasmablasts could be successfully used as a host-specific biomarker to improve diagnosis of active TB, particularly in people who are HIV positive, and facilitate administration of effective treatment to patients. Elevated IgG responses were associated with impaired peripheral T-cell responses, including reduced T-cell numbers and low M tuberculosis-specific IFNγ production.

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Related in: MedlinePlus

Assessment and comparison of peripheral blood T-cell counts, BCG-specific IgG titres and Mycobacterium tuberculosis (Mtb)-specific interferon (IFN)-γ production in patients with different clinical forms of tuberculosis (TB). Red symbols represent patients with HIV infection. (A) Total peripheral CD3 T-cell counts were determined in cases with active TB (circles), latent TB (squares), and non-TB controls (triangles). (B) Correlation analysis of peripheral blood CD3 T-cell counts and BCG-specific IgG titres among patients with active TB (circles). (C) Peripheral CD4 T-cell counts in patients who were HIV negative or HIV positive with active TB (circles) or latent TB (squares). (D) Correlation analysis of peripheral blood CD4 T-cell counts and Mtb-specific IFNγ production in vitro among patients with latent TB (squares). (E) Total peripheral CD3 T-cell counts and (F) Mtb-specific IFNγ production in vitro in patients with pulmonary TB (PTB), pleural TB or lymph node TB (LNTB) are shown. Correlation analysis of peripheral blood CD4 T-cell counts and (G) Mtb-specific IFNγ production in vitro or (H) BCG-specific IgG titres among patients who were HIV negative (open symbols) or HIV positive (red symbols) with TB lymphadenitis. Graphs are presented as scatter dot plots and the solid bars indicate the median values for each group whereas the dashed lines indicate the positive cut-off level determined for IFNγ ≥0.35 (IU/ml) and IgG titres ≥0.425 (OD). T-cell counts are presented as cells/ml. Statistical analyses included the Kruskal–Wallis and Spearman's correlation tests. A value of r=1 for the correlation coefficient rs indicates a perfect positive correlation whereas r=−1 indicates a perfect negative or inverse correlation. *p<0.05, **p<0.01 and ***p<0.001.
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thoraxjnl2012201817F3: Assessment and comparison of peripheral blood T-cell counts, BCG-specific IgG titres and Mycobacterium tuberculosis (Mtb)-specific interferon (IFN)-γ production in patients with different clinical forms of tuberculosis (TB). Red symbols represent patients with HIV infection. (A) Total peripheral CD3 T-cell counts were determined in cases with active TB (circles), latent TB (squares), and non-TB controls (triangles). (B) Correlation analysis of peripheral blood CD3 T-cell counts and BCG-specific IgG titres among patients with active TB (circles). (C) Peripheral CD4 T-cell counts in patients who were HIV negative or HIV positive with active TB (circles) or latent TB (squares). (D) Correlation analysis of peripheral blood CD4 T-cell counts and Mtb-specific IFNγ production in vitro among patients with latent TB (squares). (E) Total peripheral CD3 T-cell counts and (F) Mtb-specific IFNγ production in vitro in patients with pulmonary TB (PTB), pleural TB or lymph node TB (LNTB) are shown. Correlation analysis of peripheral blood CD4 T-cell counts and (G) Mtb-specific IFNγ production in vitro or (H) BCG-specific IgG titres among patients who were HIV negative (open symbols) or HIV positive (red symbols) with TB lymphadenitis. Graphs are presented as scatter dot plots and the solid bars indicate the median values for each group whereas the dashed lines indicate the positive cut-off level determined for IFNγ ≥0.35 (IU/ml) and IgG titres ≥0.425 (OD). T-cell counts are presented as cells/ml. Statistical analyses included the Kruskal–Wallis and Spearman's correlation tests. A value of r=1 for the correlation coefficient rs indicates a perfect positive correlation whereas r=−1 indicates a perfect negative or inverse correlation. *p<0.05, **p<0.01 and ***p<0.001.

Mentions: Total T-cell counts determined in peripheral blood of the study subjects revealed that the levels of CD3 T cells (figure 3A), and CD4 and CD8 T cells (data not shown), were clearly lower in patients with active TB compared with the other groups, particularly when compared with latent TB cases (p<0.001). We also observed a significant inverse correlation (r=−0.311, p=0.004) between CD3 T-cell counts and BCG-specific IgG titres among patients with active TB (figure 3B) but not among asymptomatic individuals (data not shown). CD4 T-cell numbers were also significantly (p<0.05) lower in active TB patients who were HIV negative or HIV positive compared with individuals with latent TB (figure 3C). Accordingly, there was a significant correlation (r=0.303, p=0.042) between CD4 T cells and Mtb-specific IFNγ production among individuals with latent TB (figure 3D) but not among patients with active TB disease (data not shown).


BCG-specific IgG-secreting peripheral plasmablasts as a potential biomarker of active tuberculosis in HIV negative and HIV positive patients.

Ashenafi S, Aderaye G, Zewdie M, Raqib R, Bekele A, Magalhaes I, Lema B, Habtamu M, Rekha RS, Aseffa G, Maeurer M, Aseffa A, Svensson M, Andersson J, Brighenti S - Thorax (2012)

Assessment and comparison of peripheral blood T-cell counts, BCG-specific IgG titres and Mycobacterium tuberculosis (Mtb)-specific interferon (IFN)-γ production in patients with different clinical forms of tuberculosis (TB). Red symbols represent patients with HIV infection. (A) Total peripheral CD3 T-cell counts were determined in cases with active TB (circles), latent TB (squares), and non-TB controls (triangles). (B) Correlation analysis of peripheral blood CD3 T-cell counts and BCG-specific IgG titres among patients with active TB (circles). (C) Peripheral CD4 T-cell counts in patients who were HIV negative or HIV positive with active TB (circles) or latent TB (squares). (D) Correlation analysis of peripheral blood CD4 T-cell counts and Mtb-specific IFNγ production in vitro among patients with latent TB (squares). (E) Total peripheral CD3 T-cell counts and (F) Mtb-specific IFNγ production in vitro in patients with pulmonary TB (PTB), pleural TB or lymph node TB (LNTB) are shown. Correlation analysis of peripheral blood CD4 T-cell counts and (G) Mtb-specific IFNγ production in vitro or (H) BCG-specific IgG titres among patients who were HIV negative (open symbols) or HIV positive (red symbols) with TB lymphadenitis. Graphs are presented as scatter dot plots and the solid bars indicate the median values for each group whereas the dashed lines indicate the positive cut-off level determined for IFNγ ≥0.35 (IU/ml) and IgG titres ≥0.425 (OD). T-cell counts are presented as cells/ml. Statistical analyses included the Kruskal–Wallis and Spearman's correlation tests. A value of r=1 for the correlation coefficient rs indicates a perfect positive correlation whereas r=−1 indicates a perfect negative or inverse correlation. *p<0.05, **p<0.01 and ***p<0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3585487&req=5

thoraxjnl2012201817F3: Assessment and comparison of peripheral blood T-cell counts, BCG-specific IgG titres and Mycobacterium tuberculosis (Mtb)-specific interferon (IFN)-γ production in patients with different clinical forms of tuberculosis (TB). Red symbols represent patients with HIV infection. (A) Total peripheral CD3 T-cell counts were determined in cases with active TB (circles), latent TB (squares), and non-TB controls (triangles). (B) Correlation analysis of peripheral blood CD3 T-cell counts and BCG-specific IgG titres among patients with active TB (circles). (C) Peripheral CD4 T-cell counts in patients who were HIV negative or HIV positive with active TB (circles) or latent TB (squares). (D) Correlation analysis of peripheral blood CD4 T-cell counts and Mtb-specific IFNγ production in vitro among patients with latent TB (squares). (E) Total peripheral CD3 T-cell counts and (F) Mtb-specific IFNγ production in vitro in patients with pulmonary TB (PTB), pleural TB or lymph node TB (LNTB) are shown. Correlation analysis of peripheral blood CD4 T-cell counts and (G) Mtb-specific IFNγ production in vitro or (H) BCG-specific IgG titres among patients who were HIV negative (open symbols) or HIV positive (red symbols) with TB lymphadenitis. Graphs are presented as scatter dot plots and the solid bars indicate the median values for each group whereas the dashed lines indicate the positive cut-off level determined for IFNγ ≥0.35 (IU/ml) and IgG titres ≥0.425 (OD). T-cell counts are presented as cells/ml. Statistical analyses included the Kruskal–Wallis and Spearman's correlation tests. A value of r=1 for the correlation coefficient rs indicates a perfect positive correlation whereas r=−1 indicates a perfect negative or inverse correlation. *p<0.05, **p<0.01 and ***p<0.001.
Mentions: Total T-cell counts determined in peripheral blood of the study subjects revealed that the levels of CD3 T cells (figure 3A), and CD4 and CD8 T cells (data not shown), were clearly lower in patients with active TB compared with the other groups, particularly when compared with latent TB cases (p<0.001). We also observed a significant inverse correlation (r=−0.311, p=0.004) between CD3 T-cell counts and BCG-specific IgG titres among patients with active TB (figure 3B) but not among asymptomatic individuals (data not shown). CD4 T-cell numbers were also significantly (p<0.05) lower in active TB patients who were HIV negative or HIV positive compared with individuals with latent TB (figure 3C). Accordingly, there was a significant correlation (r=0.303, p=0.042) between CD4 T cells and Mtb-specific IFNγ production among individuals with latent TB (figure 3D) but not among patients with active TB disease (data not shown).

Bottom Line: Immunodiagnosis of TB also included the tuberculin skin test and the interferon (IFN)-γ release assay, QuantiFERON.BCG-specific IgG titres were particularly high among patients coinfected with TB and HIV with CD4 T-cell counts <200 cells/ml who produced low levels of Mycobacterium tuberculosis-specific IFNγ in vitro.Elevated IgG responses were associated with impaired peripheral T-cell responses, including reduced T-cell numbers and low M tuberculosis-specific IFNγ production.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Center for Infectious Medicine (CIM), Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.

ABSTRACT

Background: Diagnosis of active tuberculosis (TB) among sputum-negative cases, patients with HIV infection and extra-pulmonary TB is difficult. In this study, assessment of BCG-specific IgG-secreting peripheral plasmablasts, was used to identify active TB in these high-risk groups.

Methods: Peripheral blood mononuclear cells were isolated from patients with TB and controls and cultured in vitro using an assay called Antibodies in Lymphocyte Supernatant, which measures spontaneous IgG antibody release from migratory plasmablasts. A BCG-specific ELISA and flow cytometry were used to quantify in vivo activated plasmablasts in blood samples from Ethiopian subjects who were HIV negative or HIV positive. Patients diagnosed with different clinical forms of sputum-negative active TB or other diseases (n=96) were compared with asymptomatic individuals including latent TB and non-TB controls (n=85). Immunodiagnosis of TB also included the tuberculin skin test and the interferon (IFN)-γ release assay, QuantiFERON.

Results: This study demonstrated that circulating IgG+ plasmablasts and spontaneous secretion of BCG-specific IgG antibodies were significantly higher in patients with active TB compared with latent TB cases and non-TB controls. BCG-specific IgG titres were particularly high among patients coinfected with TB and HIV with CD4 T-cell counts <200 cells/ml who produced low levels of Mycobacterium tuberculosis-specific IFNγ in vitro.

Conclusions: These results suggest that BCG-specific IgG-secreting peripheral plasmablasts could be successfully used as a host-specific biomarker to improve diagnosis of active TB, particularly in people who are HIV positive, and facilitate administration of effective treatment to patients. Elevated IgG responses were associated with impaired peripheral T-cell responses, including reduced T-cell numbers and low M tuberculosis-specific IFNγ production.

Show MeSH
Related in: MedlinePlus