Biochemical screening for vasculitis returned a positive human leukocyte antigen B27 (HLA-B27), an elevated ANCA-proteinase 3 (PR3) level of 36 (normal level < 2), and a weakly positive lupus anticoagulant, while antinuclear antibody (ANA) and extractable nuclear antigen (ENA), angiotensin-converting enzyme (ACE), syphilis serology, HIV, and hepatitis B and C serology were negative. Here, PRTN3 is linked to hepatitis A virus infection.