Question

In the test called Interferon Gamma Release Assays(IGRA) . As the number of M. Tuberculosis bacteria increase in the body of an infected patient, does the amount of interferon gamma increase, decrease or stay the same?

Pls explain.

How much is the amount of interferon gamma produced in an IGRA on ( with 1 being the most and 4 being the least)

1.A patient with latent TB.

2. A patient with a new M. Tuberculosis infection(primary infection).

3. A patient who had TB but was cured from the disease 10 yrs ago.

4. A patient with Active TB ( and has had Active TB for several years).

What are 2 reasons why MDR and XDR strains of M. Tuberculosis are becoming more common?

Thank you.