Atypical ANCA (A-ANCA):
• Atypical pattern (also known as A-ANCA) is rare and combines both cytoplasmic and perinuclear or nuclear staining, with multiple antigen specificities.
• A-ANCA can occur in association with:
Autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cirrhosis, SLE, inflammatory bowel disease , rheumatoid arthritis, and drug exposure, most often in the absence of vasculitis.