Diminished plasma levels of common γ-chain cytokines in pulmonary tuberculosis and reversal following treatment

• Published in: PloS one 2017-04, Vol.12 (4), p.e0176495-e0176495
• Main Authors: Kumar, Nathella Pavan, Banurekha, Vaithilingam V, Nair, Dina, Babu, Subash
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Antigens; Antitubercular Agents - pharmacology; Antitubercular Agents - therapeutic use; Bacteria; Biology and Life Sciences; CD4 antigen; CD8 antigen; Cell growth; Cell survival; Chains; Cytokines; Disease; Female; Hepatitis; HIV; Human immunodeficiency virus; Humans; Immune response; Immune system; Infections; Interleukin 15; Interleukin 2; Interleukin 21; Interleukin 7; Interleukins - blood; Lymphocytes; Lymphocytes T; Male; Medicine and Health Sciences; Middle Aged; Mycobacterium tuberculosis; Pathogenesis; Plasma; Plasma levels; T-Lymphocytes - cytology; T-Lymphocytes - drug effects; T-Lymphocytes - metabolism; Tuberculosis; Tuberculosis, Pulmonary - blood; Tuberculosis, Pulmonary - drug therapy; Tuberculosis, Pulmonary - immunology; Viral infections; X-rays; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0176495

The immune response to tuberculosis (TB) is T cell dependent. T cells are the major facilitators of protection and effector functions with CD4+ T cells being the most important players, followed by CD8+ T cells. The common γ-chain cytokines IL-2, IL-7, IL-15, and IL-21 play a vital role in peripheral T cell growth and survival. However, the role of common γ-chain cytokines in pulmonary TB (PTB) is poorly understood. To examine the association of circulating common γ-chain cytokines with TB disease or infection, we examined the systemic levels of IL-2, IL-7, IL-15, and IL-21 in individuals with PTB, latent TB (LTB) or no TB infection (NTB). We also examined the levels of these cytokines in PTB individuals before and after anti-tuberculosis treatment. Circulating levels of IL-2, IL-7 and IL-21 were significantly diminished in PTB compared to LTB or NTB individuals. Moreover, TB antigen stimulated whole blood also exhibited diminished levels of common γ-chain cytokines in PTB compared to LTB or NTB individuals. The plasma levels of common γ-chain cytokines exhibited no significant association with the severity or extent of TB disease or with bacterial burdens. However, upon standard anti-TB treatment, both the systemic as well as the TB antigen stimulated levels of IL-2, IL-7 and IL-21 were significantly increased in PTB individuals. Therefore our data demonstrate that diminished levels of common γ-chain cytokines are a common characteristic of PTB and potentially highlight the importance of boosting these responses to improve treatment outcomes.