Acetyl Cysteine (NAC)

Has anyone heard of Acetyl Cysteine (NAC)? I came across it when I was searching for Clinical Trials and found a trial that uses this supplement for Interstitial Lung Disease (ILD). I ordered some from Amazon, and the supplement has seemingly raving reviews (mostly for Bronchitis).

Wikipedia NAC
See "index" on page for ILD, etc.

A promising Amazon review. You never know ....

In search of best doctors for Sjogren's, MCTD

Found some good links for starters: 
US News Best Hospitals
Johns Hopkins Division of Rheumatology

Can any readers give me advice on how to get an appointment with a top Rheumy?

Found one .... crap, how to get an appointment with a Physician-in-Chief Emeritus? 
More on this doc ....