Study On The Correlation Between Antineutrophil Cyto-plasmic Antibodies And Systemic Lupus Erythematosus

Objective To explore the relationship between the antineutrophil cyto-plasmic antibodies(ANCA) and the pathogenesis of systemic lupus erythematosus(SLE), and to study the influence of ANCA on the organ or system damage in SLE patients and model murine, to elucidate the role of ANCA in the onset and activity of SLE, providing scientific evidence to the diagnosis and treatment of SLE.Methods We generated murine lupus-like syndrome of cGVHD by parental lymphocyte engraftment, and CB6F1 recipients were monitored for clinical signs by the following parameters: body weight, red blood cell, white blood cell and platelet, serum ANCA, anti-dsDNA and ANA autoantibodies measured by ELISA, proteinuria detected by albustix, pathologic changes of kidney tested through light microscope and electron microscope. 60 new onset patients with SLE were selected from two tertiary hospitals, and 60 healthy blood donors were recruited as controls. General information, chemical examination results and stateof the organ or system damage were collected by self-designed questionnair containing the Systemic Lupus Erythematosus Disease Activity Index(SLEDAI). The serum ANCA were measured by ELISA. Statistical analysis was performed by student t test, Mann-whitney rank sum test,χ2 test, Pearson correlation or Spearman correlation depending on the dataset using SPSS 13.0 software.Results Animal studies showed that, the body weight of lupus like mice was negatively associated with the serum level of ANCA. In the 8th, 10th and 12th week, the serum level of anti-dsDNA antibodies was positively associated with the level of ANCA; Furthermore, in the 8th and 12th week, the level of ANA was positively associated with the level of ANCA; in the 12th week, 5 lupus like mice died. No difference between survivors and non-survivors in serum level of ANCA was found in the 8th week. However, in the 10th and 12th week, the serum level of ANCA was significantly higher in the non-survivors when compared with survivors. The positive rate of ANCA in the group of SLE is 33.3%,which was significant higher than that in the normal controls (33.3% versus 3.3%, P <0.001). In addition, there were significantly higher positive rate of ANCA in patients with more active SLE compared to those with less active disease(P<0.01). Compared with patients negative for ANCA, the ANCA-positive patients had significantly higher incidence of nerves disorder, myocarditis, renal damage and serositis (P<0.05). Significant differences were also found between the two groups in SLE Disease Activity Index (SLE-DAI), ESR, anti-dsDNA antibodies, anti-Sm antibodies,γ-globulin, serum C3/C4 and IgG (P<0.05). LN patients had significantly higher positive rate of ANCA than the SLE patients without nephritis (P<0.05). Significance differences were also found between the LN patients positive for ANCA and LN patients negative for ANCA in renal damage, anaemia, anti-dsDNA antibodies, IgG, anti-RNP antibodies,γ-globulin, serum C3 and anti-Sm antibodies (P<0.05).Conclusions ANCA play important role in the onset of SLE and the organ or system damage, and ANCA may serve as a useful marker for assessment of disease activity of SLE. In addition, ANCA in SLE may be used as a serological marker to differentiate LN from SLE without nephritis.