TNF-alpha and the production of Granulomas

[jbrasher]

I am writing a paper regarding the usage of TNF-Inhibiting drugs (which are commonly used to treat arthritc problems) to help prevent the formation of granulomas in diseases such as Wegener's Granulomatosis.
I was wondering if anyone could help clarify the connection between TNF and the production of granulomas.
If anyone could help me out i would greatly appreciate it.