[lee-usmle]

The patterns by which antinuclear antibodies stain may give a good diagnostic clue in rheumatological diseases.
This clue is loved by USMLE question writers and it's very important to know the diagnostic significance of each pattern.
Here's a quick review:

• Rim (Peripheral) Pattern: is very specific for SLE
• Homogenous Pattern: is also specific for SLE and can be further tested with Anti-dsDNA, Anti-ssDNA, and Anti-Smith.
• Speckled Pattern: is the most common pattern but it's the least specific is it can be seen SLE, Scleroderma, Sjogren's, Mixed Connective Tissue disease, and also in normal people.
• Diffuse Pattern: is also non specific
• Centromere Pattern: is specific for CREST
• Nucleolar Pattern: is specific for scleroderma and systemic sclerosis

Some other useful threads
http://www.usmle-forums.com/usmle-step-1-forum/749-p-anca-c-anca-causes.html
http://www.usmle-forums.com/usmle-step-1-bits-pieces/317-positive-autoimmune-antibodies-causes.html