Tuberculosis and HIV coinfection

Tuberculosis and HIV coinfection


One in three people harbor latent Mycobacterium tuberculosis (Mtb), the bacterium that causes tuberculosis (TB), but latent Mtb can develop into active TB.

Coinfection with HIV can speed the progression of latent to active TB, a process likely driven by a depletion of CD4+ T cells.

To study the immunological regulation of latent TB infection by HIV, researchers infected macaques with Mtb and simian immunodeficiency virus (SIV), mimicking Mtband HIV coinfection in humans.

In a majority of animals, Mtb replication rapidly reactivated and progressed to active TB, and pathologies associated with SIV increased. Despite the decrease in pulmonary CD4+ T cells in all coinfected macaques, one-third of the animals maintained TB latency.

For this cohort, an increase in protective immune responses, mediated by CD8+ memory T-cell proliferation and increased B-cell responses, was associated with limited Mtbreplication.

According to the authors, the findings may provide insights into natural immunity to Mtb and could help guide the development of vaccines and immunotherapies for TB and HIV.

http://www.pnas.org/content/early/2016/08/30/1611987113

Edited

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