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Enhanced frequency of neutrophils and inflammatory monocytes and diminished numbers of T and B cells in active pulmonary tuberculosis


Mycobacterium tuberculosis (M.tb) infects nearly 2 billion people worldwide. Effective immunity against M.tb infection requires co-ordinated responses from both innate and adaptive arms of immunity. To elucidate the immune responses important both in control of infection and in extra-pulmonary dissemination, we examined frequency and/or absolute numbers of T, B and NK cells, dendritic cells and other leucocyte populations in active tuberculosis patients.


The frequency as well as absolute numbers of T cells (CD3+, CD4+, CD8+ T cells), B cells and NK cells as well as the frequency of innate immune cells (neutrophils and monocytes), dendritic cell subsets (pDC & mDC ), T cell subsets (naïve, central and effector memory and regulatory T cells) was examined by flow cytometry in AFB smear positive pulmonary TB (Sm+) (n=30) and AFB smear negative pulmonary TB (Sm-) (n=24) and compared with extra- pulmonary TB (EP) (n=38).


Among the innate immune subsets, we observed significantly higher frequency of neutrophils and inflammatory monocytes in Sm+ pulmonary TB group when compared with Sm- pulmonary and EP TB group. On the other hand, the absolute numbers of CD3+ T cells, CD4+ T cells, CD8+ T cells and B cells were significantly lower in Sm+ when compared with Sm- and EP TB group.


Pulmonary TB is characterized by enhanced frequencies of neutrophils and inflammatory monocytes and diminished absolute counts of T and B cells, suggesting a crucial role for these cell populations in protection against TB disease development as well as extra-pulmonary dissemination.

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Correspondence to N Pavan Kumar.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Kumar, N.P., Hanna, L.E., Jawahar, M. et al. Enhanced frequency of neutrophils and inflammatory monocytes and diminished numbers of T and B cells in active pulmonary tuberculosis. BMC Infect Dis 12, P23 (2012).

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  • Tuberculosis
  • Pulmonary Tuberculosis
  • Innate Immune Cell
  • Dendritic Cell Subset
  • Active Pulmonary Tuberculosis