Chronic Inflammation: TB, Sarcoidosis, Myocarditis

Question 1

What would a positive TB test tell you? And what could a false-negative test be indicative of?

Answer 1

A positive tuberculin test signifies T-cell–mediated immunity to mycobacterial antigens but does not differentiate between infection and active disease. False-negative reactions may occur in the setting of certain viral infections, sarcoidosis, malnutrition, Hodgkin lymphoma, immunosuppression, and (notably) overwhelming active tuberculous disease

Question 2

What kind of Th cell mediates TB immunity?

Answer 2

Th1

Question 3

What is the difference between primary and secondary TB?

Answer 3

Primary infection occurs in a host that is not immune (get infected and it is contained in granulomas, usually go asymptomatic) and secondary occurs in a patient who was immune and the infection is reactivated or reinfected.

Question 4

What does TB do in kids?

Answer 4

Primary progressive TB. The TB spreads because body can stop it and leads to disseminated infection which can spread to the CNS. Granulomas form in ventricles, die of hydrocephalus

Question 5

What is a Ghon complex?

Answer 5

Hilar lymph nodes with the granulomatous foci in lung

Question 6

How does BCG help children in areas of the world where TB is prevalent?

Answer 6

BCG is a live attenuated vaccine. Turns the childhood primary progressive TB into latent “adult” form so that granulomas form and disseminated infection is avoided.

Question 7

How do granulomas help with containing TB and what cytokines help to recruit the granuloma initiators?

Answer 7

Mainly macrophages and T cells are recruited by IL-12, IFN-gamma (more ROS), TNF-alpha, after the innate immunity is evaded. These macrophages turn into epithelioid histiocytes.

Question 8

What’s secondary TB also called?

Answer 8

Recrudescent TB