Objective:To investigate the presence of Anti-Neutrophil Cytoplasmic Antibodies(ANCA) and their specific antigens in the patients with thromboangiitis obliterans(Buerger’s disease

TAO).Methods:The TAO group includes 23 patients.The arteriosclerosis obliterans(ASO) group includs 25 pantients and the control group is health group includs 25 volunteers.Serum samples were investigated for ANCA prevalence by indirect immunofluorescent technique in TAO group

ASOgroup and health group.the reactivity to proteinase 3(PR3)

myeloperoxidase(MPO)

cathepsin G(CG)

bactericidal/permesbility-increasing protein(BPI)

elastase(HLE) and lactoferrin(LF) was measured by ELISA in TAO group and health group.Results:(1) There are 13 of 23 patients with TAO who are tested ANCA positive by indirect immunofluorescence

the ANCA prevalence is 52.2%.Only one patient is pANCA positive among 25 patients with ASO

the prevalence is 4%

and no ANCA are found in healthy controls.(2) ANCA were predominantly found in group II(66.7%;12/18) compared to group I(33.3%;3/9) and the levels of the titre of ANCA in the group II was higher than group I.(3) Only five of 12 ANCA-positive sera reacted with MPO

three of the twelve reacted with LF

one serum is HLE positive and one is BPI positive.No serum reacted with PR3 and CG.(4) Anti-MPO

anti-LF

anti-BPI and anti-HLE autoantibodies were found only in the severe group.Conclusion:The prevalence of ANCA and levels of Anti-MPO

anti-LF

anti-BPI and anti-HLE correlated with disease severity.Therefore

detection of ANCA can be a helpful serological test for the diagnosis of thromboangiitis obliterans.