Published online Mar 27, 2015. doi: 10.5411/wji.v5.i1.16
Peer-review started: June 10, 2014
First decision: July 10, 2014
Revised: November 18, 2014
Accepted: February 4, 2015
Article in press: February 9, 2015
Published online: March 27, 2015
Mycobacterium tuberculosis (Mtb) is a pathogen that is widely distributed geographically and continues to be a major threat to world health. Bacterial virulence factors, nutritional state, host genetic condition and immune response play an important role in the evolution of the infection. The genetically diverse Mtb strains from different lineages have been shown to induce variable immune system response. The modern and ancient lineages strains induce different cytokines patterns. The immunity to Mtb depends on Th1-cell activity [interferon-γ (IFN-γ), interleukin-12 (IL-12) and tumor necrosis factor-α (TNF-α)]. IL-1β directly kills Mtb in murine and human macrophages. IL-6 is a requirement in host resistance to Mtb infection. IFN-γ, TNF-α, IL-12 and IL-17 are participants in Mycobacterium-induced granuloma formation. Other regulating proteins as IL-27 and IL-10 can prevent extensive immunopathology. CXCL 8 enhances the capacity of the neutrophil to kill Mtb. CXCL13 and CCL19 have been identified as participants in the formation of granuloma and control the Mtb infection. Treg cells are increased in patients with active tuberculosis (TB) but decrease with anti-TB treatment. The increment of these cells causes down- regulation of adaptive immune response facilitating the persistence of the bacterial infection. Predominance of Th2 phenotype cytokines increases the severity of TB. The evolution of the Mtb infection will depend of the cytokines network and of the influence of other factors aforementioned.
Core tip: Cytokines are proteins that can alter the behavior or properties of the cell itself or of another cell. These proteins are involved in the immunopathology of different diseases. Study of the cytokines in Mycobacterium tuberculosis infection is very important. They participate in the establishment, persistence and evolution of the infection. The intricate complexity of these regulating proteins stimulate the investigation to the search of more effective treatments that permit the eradication of a disease as tuberculosis which is one of the leading causes of mortality and morbidity worldwide despite efforts made by the scientific community.