Bactericidal permeability increasing protein (BPI)-ANCA markiert chronische entzundliche darmerkrankungen und entzundliche hepatobiliare erkrankungen

Background: Bactericidal permeability increasing protein (BPI) is an antibacterial product of neutrophilic granulocytes that can serve as target antigen for antineutrophil cytoplasmic antibodies (ANCA). The clinical associations of autoantibodies angainst BPI (BPI-ANCA) are essentially unclear. Patients and Methods: 587 sera from patients with chronic inflammatory bowel diseases, inflammatory hepatobiliary diseases, primary systemic vasculitides and other rheumatological diseases were examined for BPI-ANCA by monospecific ELISA and a standard indirect innnunofluorescence test for ANCA. Results: The prevalence of BPI-ANCA was 43% in ulcerative colitis, 23% in Crohn's disease, 35% in primary sclerosing cholangitis, 25% in primary biliary cirrhosis and 29% in autoimmune hepatitides. In a spectrum of systemic vasculitides, in flammatory joint diseases and collagen vascular diseases the prevalence was only 3 to 11%. In contrast to PR3-ANCA and MPO- ANCA, BPI-ANCA was not associated with a particular pattern of fluorescence in the immunofluorescence test on ethanol- and formalin-fixed neutrophils. Conclusion: This study shows that BPI-ANCA is the third ANCA specificity, besides PR3-ANCA and MPO-ANCA, with a limited spectrum of clinical associations. The diagnostic and prognostic relevance of BPI-ANCA in the above clinical conditions is being examined prospectively.