Comparison Of Two Methods For Detection Of Anti-neutrophil Cytoplasmic Antibody And The Target Antigens Expressed In ANCA Associated Glomerulonephritis

Object To examine the test characteristics of immunofluorescence(IIF) and enzyme-linked immunosorbent assays(ELISA) in a consecutive series of patients under evaluation for anti-neutrophil cytoplasmic antibody(ANCA)-associated vasculitis (AAV), analysis of involved organ characteristics of patients with AAV and to investigate the relationship between the serum LAMP-2antibody levels and ANCA-associated glomerulonephritis (ANCA-associated GN).Methods3852non-duplicated ANCA specimens and medical data of the relevant cases were collected, and all of the data were submitted from different departments of General Hospital of Tianjin Medical University from July2011to May2013. IIF method and ELISA method were combined to give ANCA detection on these specimens..The clinical data of87cases of diagnosed AASV patients were retrospectively analyzed, and33cases of untreated ANCA associated GN patients confirmed by renal biopsy were screened out. Over the same period,30cases of healthy people were collected as healthy control. ANCA were detected by indirect immunofluorescence and ELISA, analyze the correlation with disease activity and anti-LAMP-2antibody levels through observed the dynamic change of anti-LAMP-2antibody levels in new onset ANCA-associated GN and remission patientsResult The positive rate of ANCA detected by ELISA method was higher than that by IIF method(x2=14.405, p<0.001). The overall compliance rate of two detection methods was94.93%(Kappa=0.611, p<0.001). The misdetection rate was1.84%in ELISA method and3.21%in IIF method. The misdetection rates of IIF method in anti-PR3-positive specimen group and anti-BPI-positive specimen group were higher than that in anti-MPO-positive specimen group(x2=25.050, p<0.001;x2=11.623, p<0.001). AAV was more common in men over60years old and the type was common in microscopic polyangiitis. AASV patients were often involved with the kidney. The concentrations of anti-LAMP-2antibody levels before the treatment was higher than the after and healthy contrals(p<0.001).Serum anti-LAMP-2antibody levels has on differed significantly between patients with remission patients and healthy controls (p<0.001).As detected by IIF, the levels of anti-LAMP-2antibody in Atypical-ANCA group was more than that in P-ANCA and C-ANCA groups (p<0.001). Concentrations of anti-LAMP-2antibody showed a strongly positive correlation with ESR, Cr, BUN, proteinuria, crescent proportion and BVAS score and a negative correlation with Hb,ALB and CCr.Conclusion The results show that the overall compliance rate of two detection methods was94.93%(Kappa=0.611,p<0.001), the consistency of2methods was general (Kappa=0.611, P<0.001), the misdetection rate was19.34%in ELISA method and33.78%in IIF method of all positive specimens. If only use one method to detect ANCA, will lead to a high proportion of positive samples were missing.lt is very necessary to test ANCA by2methods when the clinical suspicion the patients with vasculitis, rheumatic disease and pulmonary interstitial fibrosis, in order to reduce the leakage diagnosis of related diseases.We suggest at anti-LAMP-2antibody could play an important role in the pathogenesis of ANCA-associated GN in the presence of Atypical-ANCA detected by IIF.