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.