Table 1.

Potential impact of understanding functional T cell lineages in GCA

A.	Diagnostics
	Determine T cell frequencies in diagnostic work-up
	Monitor T cell frequencies as a marker of disease activity
	Evaluate type and frequency of tissue-infiltrating T cells
	Example: IL-17-producing patients with MS are non-responders to IFN-β Tx
B.	Therapeutics
	Block T cell cytokine to disrupt inflammatory end pathway
	Target antigen-presenting cells to inhibit T cell differentiation
	Interrupt T cell recruitment to vessel wall or in situ activation
	Example: Therapeutic anti-IL-17 antibodies in Rheumatoid Arthritis
C.	Pathogenic concepts
	Use disease-relevant T cells as a tool to identify the disease instigator(s)
	Separate GCA from other disease processes
	Example: Chromogranin-specific T cells cause islet cell destruction and diabetes