Genetic discovery provides clues to how TB may evade the immune system

This photomicrograph reveals Mycobacterium tuberculosis bacteria using acid-fast Ziehl-Neelsen stain; Magnified 1000 X. The acid-fast stains depend on the ability of mycobacteria to retain dye when treated with mineral acid or an acid-alcohol solution such as the Ziehl-Neelsen, or the Kinyoun stains that are carbolfuchsin methods specific for M. tuberculosis. Credit: public domain

The largest genetic study of tuberculosis (TB) susceptibility to date has led to a potentially important new insight into how the pathogen manages to evade the immune system, according to research published today in the journal Nature Genetics.

Researchers found that variants of the gene ASAP1 on chromosome 8 affect individuals’ susceptibility to TB. The gene encodes a protein carrying the same name and is highly expressed – in other words, larger amounts of the protein are found – in a particular type of immune cells known as dendritic cells that play a key role in kick-starting the body’s immune response to incoming pathogens.