Search

Aim: Our previous study suggested that patients with MPO-ANCA (myeloperoxidase antineutrophil cytoplasmic autoantibodies)-positive Wegener's granulomatosis (WG) were common in Chinese, indicating that patients with MPO-ANCA could manifest as either WG or microscopic polyangiitis (MPA). The aim of this study was to compare the immunological characteristics of MPO-ANCA in patients with WG and MPA., Methods: Fifteen patients with WG and 21 patients with MPA were enrolled in the current study. Anti-MPO IgG subclasses and their titres were detected by antigen-specific enzyme-linked immunosorbent assays (ELISA); affinity was assessed by antigen-inhibition ELISAs. The sera from all patients were employed to inhibit biotin conjugated affinity-purified human anti-MPO antibodies (Probe-biotin), from plasma exchange of a patient with MPA, in a competitive inhibition ELISAs system., Results: All four anti-MPO subclasses could be detected in sera from patients with WG and MPA. The titres of anti-MPO IgG4 subclass in patients with WG were significantly higher than those with MPA (1:1878 vs 1:218, P < 0.005). The affinity constants of MPO-ANCA were comparable between patients with WG and MPA (0.3-70/M vs 0.3-140/M respectively). Eleven out of the 15 sera and 18 out of the 21 sera could inhibit the binding of the Probe-biotin in patients with WG and MPA respectively. The average inhibition rate was 47.7% +/- 11.5% and 61.7% +/- 14.5% respectively (P < 0.05)., Conclusion: MPO-ANCA IgG4 subclass might play a role in the development of WG. The MPO-ANCA in WG and MPA might recognize overlapping but different epitopes on native MPO molecule. The difference in immunological characteristics of MPO-ANCA might contribute to different disease entities.

Background: The kidney is one of the organs affected in patients with propylthiouracil (PTU)-associated antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis. We present a series of Chinese patients with renal involvement in PTU-associated ANCA-positive vasculitis and describe their clinical and pathological characteristics., Methods: Clinical and pathological data from patients with PTU-associated ANCA-positive vasculitis with renal involvement, diagnosed in Peking University First Hospital, were collected and analyzed retrospectively., Results: Nineteen patients with PTU-associated ANCA-positive vasculitis were treated at Peking University First Hospital between December 1999 and December 2005, and 15 of them had renal involvement. Of the 15 patients, 13 were female and 2 were male, with an average age of 26.3 +/- 11.8 years. All 15 patients were perinuclear ANCA positive with specificities to myeloperoxidase (15 of 15), cathepsin G (9 of 15), human leukocyte elastase (8 of 15), lactoferrin (7 of 15), azurocidin (5 of 15), and proteinase 3 (4 of 15). Duration of PTU administration was 43.0 +/- 31.2 months. All 15 patients had clinical markers of renal involvement, including hematuria (100%), proteinuria (100%), and renal function abnormality (47%). All 15 patients underwent percutaneous renal biopsy. Ten patients had necrotizing crescentic glomerulonephritis, and 7 of these 10 patients had immune complex deposition. Three patients had minimal involvement, 2 patients had immunoglobulin A nephropathy, and 2 patients had membranous nephropathy. PTU treatment was discontinued in all 15 patients. All except 2 patients with minimal renal involvement received immunosuppressive treatment. Eleven of 15 patients achieved complete clinical remission., Conclusion: Renal involvement in our case series of patients with PTU-associated ANCA-positive vasculitis was heterogeneous, and nearly half our patients had renal immune complex deposition.

Goodpasture disease (GP) is defined by the presence of anti-glomerular basement membrane (anti-GBM) antibodies and rapidly progressive glomerulonephritis. Besides anti-GBM, many patients with GP produce anti-neutrophil cytoplasmic antibodies (ANCA). For elucidation of the pathophysiologic significance of ANCA in this setting, epitope and antigen specificity of the anti-GBM antibodies and antigen specificity of ANCA were studied. Bovine testis alpha(IV)NC1 (tNC1); recombinant human alpha1, alpha3, alpha4, and alpha5(IV)NC1 (ralpha1 through ralpha5); and three chimeric proteins that contain previously defined epitope regions designated E(A), E(B), and S2 were used to examine the anti-GBM antibodies by ELISA in 205 Chinese patients with GP with or without ANCA. In the 205 anti-GBM antibody-positive sera, 63 (30.7%) were also ANCA positive (61 myeloperoxidase-ANCA and six proteinase 3-ANCA, four being triple positive). All 205 sera recognized tNC1 and ralpha3(IV)NC1. In the double-positive group, 54.0, 66.7, 71.4% of the sera could recognize ralpha1, ralpha4, and ralpha5, respectively, compared with 49.3, 60.6, and 55.6% for patients with anti-GBM antibodies alone. The levels of the antibodies to ralpha3, tNC1, and the alpha3/alpha1 ratio were lower in the double-positive group than that in patients with anti-GBM antibody alone (P < 0.05). Most of the sera could recognize the epitope regions E(A), E(B), and S2, but the absorbance values to E(A), E(B), and S2 were lower in double-positive group (P < 0.05). Double-positive patients had a broader spectrum of anti-GBM antibodies and lower levels of antibodies against alpha3(IV)NC1 compared with that of patients with anti-GBM antibodies alone.

Objective: Propylthiouracil (PTU) has been known to induce myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) positive vasculitis. Our previous study indicated that the increase of avidity of MPO-ANCA might be associated with the occurrence of clinical vasculitis in patients with PTU-induced ANCA. The current study aimed to follow-up the avidity and titre of anti-MPO antibodies in sequential sera from patients with PTU-induced ANCA-associated systemic vasculitis (AASV)., Methods: Six patients with PTU-induced vasculitis were enrolled in the current study. Serial sera in both active phase and in remission were collected. MPO-ANCA avidity was assessed by antigen-inhibition enzyme-linked immunosorbent assays (ELISAs), and avidity constant (aK) was determined as the reciprocal value of the MPO molar concentration in the liquid phase resulting in 50% inhibition of anti-MPO antibody binding to MPO in solid phase ELISA. Titres of MPO-ANCA were determined by using serial serum dilutions in MPO-ELISA., Results: After cessation of PTU and initiation of immunosuppressive therapy, the avidity and titre of MPO-ANCA decreased significantly during follow-up in sera from all the patients, and the avidity decreased much more quickly than the titres., Conclusion: Our study indicates that avidity of anti-MPO antibodies might be more closely associated with clinical vasculitis than titre.

Pauci-immune crescentic glomerulonephritis (CrGN) is one of the most common causes of rapidly progressive glomerulonephritis. The majority of patients with pauci-immune CrGN had circulating antineutrophil cytoplasmic autoantibody (ANCA). However, patients with ANCA-negative pauci-immune CrGN were not investigated fully. This study aimed to analyze the characteristics of this subgroup of patients. Patients whose pauci-immune CrGN was diagnosed from 1997 to 2006 in one center were studied retrospectively. The criteria of pauci-immune was defined as "the intensity of glomerular immunoglobulins staining by direct immunofluorescence assay in renal sections was negative to 1+ staining on a scale of 0 to 4+." Clinical and pathologic characteristics were compared between patients with and without ANCA. Among the 85 patients with pauci-immune CrGN, 28 (32.9%) were ANCA negative. Compared with the 57 ANCA-positive patients, the ANCA-negative patients were much younger (39.7 +/- 17.0 versus 57.6 +/- 14.0 yr; P < 0.001). The level of urinary protein and the prevalence of nephrotic syndrome were significantly higher in ANCA-negative patients than that in ANCA-positive patients (P < 0.01 and P < 0.001, respectively). However, the prevalence of extrarenal involvement was significantly lower in ANCA-negative patients than that in ANCA-positive patients. The renal survival was poorer in ANCA-negative patients than that in ANCA-positive ones (P < 0.05). ANCA-negative pauci-immune CrGN was not rare and might represent an independent disease entity from ANCA-positive vasculitis.

Propylthiouracil (PTU) could induce antineutrophil cytoplasmic antibody (ANCA) associated vasculitis. This study aimed to investigate the inhibitory effects on MPO oxidation activity by PTU and MPO-ANCA from patients with primary microscopic polyangiitis (MPA) and PTU-induced vasculitis. IgG preparations were purified from MPO-ANCA-positive sera from seven patients with PTU-induced vasculitis and ten patients with primary MPA. The oxidation activity of MPO was measured in the presence of PTU and MPO-ANCA-positive IgG preparations from patients with PTU-induced vasculitis and primary MPA respectively. PTU could competitively inhibit the oxidation activity of MPO dose dependently. MPO-ANCA-positive IgG preparations from 6/7 patients with PTU-induced vasculitis and only 3/10 from patients with primary MPA could inhibit the MPO activity in a dose-dependent manner. In conclusions, the oxidation activity of MPO could be inhibited by PTU and PTU-induced MPO-ANCA in a dose-dependent manner, which might be involved in the pathogenesis PTU-induced vasculitis.

Aim: To analyse the clinical and pathological characteristics of Chinese patients with immune complex deposition in kidney in anti-neutrophil cytoplasmic antibodies (ANCA)-positive vasculitis., Methods: Enrolled in this study are patients with immune complex deposition in kidney in ANCA-positive vasculitis diagnosed in Peking University First Hospital. Their clinical and pathological data were collected and analysed., Results: Twenty-three patients were eligible. Fifteen patients were with microscopic polyangiitis and eight patients were with Wegener's granulomatosis. The mean age was 48.8 years and with a male/female ratio of 10/13. The interval, between onset of disease and the diagnosis of disease, was 429.6 +/- 693.3 days. All patients had clinical evidence of renal involvement. The major immunoglobulin deposited was IgM and the main locations were mesangial and sub-epithelial area. Four patients also presented features of membranous nephropathy and six patients presented features of IgA nephropathy. About 52.2% of patients had hypocomplementaemia. All patients received immunosuppressive therapy and all of them achieved clinical remission. Patients were followed for about 28.8 +/- 25.3 months. Nine patients kept clinical remission, nine patients progressed to end-stage renal disease and five patients died. When these patients are compared with patients who had classical pauci-immune vasculitis, they had greater proteinuria (P < 0.05), higher prevalence of hypocomplementaemia (P < 0.05) and greater glomerular cellularity (P < 0.05)., Conclusion: The present study showed that the features of patients with ANCA-associated vasculitis with immune complex deposition in kidney were similar with classical 'pauci-immune' vasculitis except for more proteinuria, more hypocomplementaemia and greater glomerular hypercellularity.

Objective: Antineutrophil cytoplasmic antibody (ANCA) has been well documented in association with propylthiouracil (PTU), and some patients with PTU-induced ANCA also develop clinical vasculitis. The aim of the current study was to detect ANCA specificities in sera from patients with PTU-induced ANCA with and without clinical vasculitis., Methods: Sera from 65 patients with PTU-induced ANCA were collected, and 27 of these patients were diagnosed with PTU-induced ANCA associated systemic vasculitis (AASV). Indirect immunofluorescence assay and antigen-specific ELISAs were used to detect ANCA and their antigen specificities. The seven known target antigens included myeloperoxidase (MPO), proteinase 3, human leukocyte elastase, lactoferrin, cathepsin G, azurocidin and bactericidal/permeability-increasing protein (BPI)., Results: In IIF assay, P-ANCA was found in 58/65 (89.2%) sera, C-ANCA in two, both P-ANCA and C-ANCA in five, respectively. MPO (60%) and lactoferrin (63.1%) were the two most common target antigens detected in sera from all the patients. 25/27 sera from patients with PTU-induced AASV recognized multiple target antigens, which was significantly higher than those (13/38) from patients without (P<0.001). Except anti-BPI antibodies, the prevalence of antibodies against the other six target antigens was significantly higher in patients with clinical vasculitis than that in patients without (P<0.05, respectively)., Conclusion: Antibodies against multiple ANCA specific antigens, especially the antigens rather than MPO and PR3, might be the characteristic of PTU-induced ANCA. Patients with antibodies against more ANCA specific antigens might be at increased risk of developing overt clinical vasculitis. The mechanism of ANCA production in PTU-induced cases was different from that in primary AASV.

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis (AASV) is a systemic autoimmune disease. A number of cases have been found to have antiglomerular basement membrane (GBM) antibody-positive serum. The purpose of the current article is to investigate the prevalence of anti-GBM antibodies in sera from a large cohort of Chinese patients with AASV and to characterize the clinical and pathological features of the 'double positive' patients., Methods: Sera from 652 patients with AASV were screened by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot analysis using purified human alpha(IV)NC1 as antigen. Antigen specificity of anti-GBM antibodies was determined by ELISA using recombinant human alpha 3(IV)NC1 as solid phase ligand. Clinical and pathological data of patients with both ANCA and anti-GBM antibodies were analyzed retrospectively., Results: 61/652 (9.36%) sera from patients with AASV were serum anti-GBM antibody positive and all recognized recombinant human alpha 3(IV)NC1. All the cases had renal involvement, 37/48 (77.1%) cases had pulmonary involvement, non-specific symptoms and other multisystem involvements were common. The renal survival was 14.6% (7/48) and patient survival was 37.5% (18/48) respectively at the end of 1 year. The following factors predicted poor prognosis: (1) serum creatinine >700 micromol/l (p = 0.034); (2) oliguria or anuria on diagnosis (p = 0.001); (3) high percentage (>85%) of glomeruli with crescents (p = 0.011); (4) high titer anti-GBM antibodies (p = 0.003), and (5) hemoptysis (p = 0.049)., Conclusion: Patients with double antibodies were not rare in AASV. They had multisystem involvement but poor short-term prognosis.Anti-GBM antibodies should be detected on diagnosis of AASV, especially for old ages., ((c) 2007 S. Karger AG, Basel.)

Background: Cytoplasmic antineutrophil cytoplasmic autoantibodies (cANCA)/proteinase-3(PR3)-ANCA was considered the serologic diagnostic marker for Wegener's granulomatosis (WG). However, Chinese patients with MPO-ANCA positive WG were frequently diagnosed. We now analyze the characteristics of patients with MPO-ANCA positive WG and investigate the difference between patients with MPO-ANCA and PR3-ANCA., Methods: Patients with WG were selected according to both Chapel Hill Consensus Conference definition and American College of Rheumatology (ACR) classification criteria in 500 Chinese patients with ANCA-associated systemic vasculitides. The clinical manifestions were compared between patients with MPO-ANCA and with PR3-ANCA., Results: Eight-nine patients fulfilled the diagnostic criteria of WG: 54/89(60.7%) were MPO-ANCA positive, 34/89(38.2%) were PR3-ANCA positive. Patients with MPO-ANCA were predominantly female compared with patients with PR3-ANCA. Patients with MPO-ANCA also had multisystem involvement. However, the prevalences of arthagia, skin rash, ophthalmic and ear involvement were significantly lower in patients with MPO-ANCA than those in patients with PR3-ANCA (46.3% vs. 70.6%, P < 0.05; 20.4% vs. 44.1%, P < 0.05; 27.8% vs. 58.8%, P < 0.01; 40.7% vs. 67.6%, P < 0.05, respectively). The prevalence of elevated initial serum creatinine was significantly higher in patients with MPO-ANCA than that in patients with PR3-ANCA (81.5% vs. 61.8%, chi(2) = 4.20, P < 0.05)., Conclusion: Patients with MPO-ANCA positive WG were not rare in Chinese.

Objective: Antineutrophil cytoplasmic autoantibodies (ANCA) were found in patients with systemic lupus erythematosus (SLE). Cathepsin G and lactoferrin were the major target antigens. However, some ANCA-positive sera did not recognize either of them. The present study was to investigate the unknown target antigens of ANCA in patients with SLE and their clinical significance., Methods: Sera were collected from 72 patients with SLE. ANCA were detected in both indirect immunofluorescence and antigen-specific enzyme-linked immunosorbent assay (ELISA). Mixed neutrophil granules were separated from normal human peripheral neutrophils; soluble acid extracts in non-reducing conditions were used as antigens in western blot analysis to detect ANCA., Results: SLE sera could blot a few bands. Interestingly, 14/72 (19.4%) sera recognized a novel 69 kDa protein band and 10/72 (13.9%) sera recognized the 55 kDa protein band, which might be bactericidal/permeability-increasing protein (BPI). The 69 kDa target antigen was different from the known target ANCA antigens such as cathepsin G and lactoferrin. Further study revealed that the percentages of patients with photosensitivity and oral ulcer in the anti-69 kDa autoantibodies-positive group were significantly higher than those in the anti-69 kDa autoantibodies-negative group (57.1%vs 10.3%, P < 0.005 and 50.0%vs 12.1%, P < 0.05, respectively)., Conclusions: A 69 kDa protein in human neutrophil granules was identified as a novel target antigen of ANCA in patients with SLE. The anti-69 kDa autoantibodies might be associated with photosensitivity and oral ulcer in patients with SLE.

Objective: To investigate the distribution of IgG subclass of anti-myeloperoxidase (MPO) antibodies, a kind of antineutrophil cytoplasmic autoantibody (ANCA), in sera from patients with propylthiouracil (PIU)-induced vasculitis., Methods: Serum samples were collected from 12 patients with PIU-induced MPO ANCA positive vasculitis, both sera of active and remission phases were collected from 10 of which, and only serum of active phase was collected from 2 of which. Anti-MPO IgG subclasses were detected by antigen-specific ELISA. The distribution of anti-MPO IgG subclasses in PIU-induced vasculitis was compared with that in primary vasculitis., Results: Anti-MPO IgG3 subclass was not detected in the sera from both active and remission phases of PIU-induced vasculitis. In the active phase the following anti-MPO IgG subclasses were found: IgG1 (12/12, 100%), IgG2 (1/12, 66.7%), and IgG4 (7/12, 58.3%). In the remission phase, the following anti-MPO IgG subclasses were found: IgG1 (9/10, 90%), IgG2 (4/10, 40%), and IgG4 (2/10, 20%). The titer of anti-MPO IgG4 subclass remained high in the remission phase in primary vasculitis; however, it decreased significantly after the cessation of PIU use in PIU-induced vasculitis., Conclusion: The distribution of anti-MPO IgG subclasses in the sera of the patients with PIU-induced vasculitis is different from that of the patients with primary vasculitis. The higher titer pf MPO-ANCA in the sera of the patients with PIU-induced vasculitis may be associated with the repeated PIU stimulation.

Background: Anti-neutrophil cytoplasmic autoantibodies (ANCA) are serological markers of ANCA-associated small vessel vasculitis (AASV) which is one of common autoimmune diseases in Caucasian elderly population., Objective: To analyze the clinical and pathological characteristics of Chinese elderly patients with AASV., Methods: One-hundred forty one Chinese patients with AASV over 65 years old, diagnosed between 1997 and 2001 in the Institute of Nephrology of Peking University First Hospital, were retrospectively studied and their clinical and pathological data were analyzed., Results: Patients diagnosed with AASV patient increased chronologically with the yearly ratio in 2000 and 2001 significantly (P < 0.05) higher than that in 1998 and before. Of the 141 patients, 72 were male and 69 were female with an average age of 68.2 years. 13 of the 141 were cytoplasmic ANCA (cANCA) positive and all recognized proteinase 3 (PR3). The other 128 were perinuclear ANCA (pANCA) positive and 120/128 recognized MPO, 8/128 recognized both PR3 and MPO. Less than 50% of the patients were correctly diagnosed within 3 months. Clinically, 78% of the patients had fever and fatigue, 52.5% had body weight loss, 96.4% had kidney involvement, of which 75% had elevated serum creatinine and 30.8% had acute renal failure. 76.6% had lung involvement, over half of them had hemoptysis or lung infiltrates. Other clinical manifestations included arthralgia (48.2%), muscle pain (39.7%), gastrointestinal symptoms (39.7%), eye involvement (28.3%) and ENT involvement (31.2%). In laboratory examinations, 94.4% of the patients had anemia, 62.4% had increased WBC count, 93.6% had increased ESR and 55.1% had increased CRP., Conclusions: More and more patients with AASV were diagnosed in Chinese elderly. Kidney was the most vulnerable organ to be involved and lung was the most important extra-renal organ to be affected. For elderly patients with multi-organ damage, an ANCA test should be performed in order to make an early diagnosis and start therapy in time., (Copyright 2004 Elsevier Inc.)

Objective: Antithyroid drugs such as propylthiouracil (PTU) and methimazole (MMI) are common medications in Chinese patients with hyperthyroidism and PTU-induced antineutrophil cytoplasmic antibody (ANCA) positive vasculitis has been reported. The current cross-sectional study aimed to investigate the prevalence and the target antigens of ANCA in Chinese patients with hyperthyroidism pre- and post-antithyroid medication therapy., Methods: Sera from 216 patients with hyperthyroidism in our hospital were collected from January to July in 2002. Patients were divided into four groups: untreated (n = 34); treated with PTU (n = 62); treated with MMI (n = 77); and treated with both PTU and MMI (n = 43). Indirect immunofluorescence (IIF) assay was used to detect ANCA and ANA. Antigen-specific ELISAs were used to detect antigen specificities. The known antigens included myeloperoxidase (MPO), proteinase 3 (PR3), human leukocyte elastase (HLE), lactoferrin, bactericidal/permeability-increasing protein (BPI), cathepsin G and azurocidin., Results: 33/216 sera were IIF positive, 20 of the 33 samples were ANCA positive, 11 samples were ANA positive, and two samples were both P-ANCA and ANA positive. The prevalence of positive ANCA in patients receiving PTU (14/62, 22.6%) was significantly higher than that of untreated patients (1/34, 2.9%) and patients treated with MMI (0/77, 0), P < 0.017. Of the 22 IIF-ANCA positive samples, 12 (54.5%) sera recognized lactoferrin, seven (31.8%) sera recognized HLE, four sera recognized MPO and azurocidin respectively, three sera recognized PR3 and cathepsin G respectively, and one serum recognized BPI. Six of the 22 (27.3%) patients with ANCA positive had clinical evidence of vasculitis. All patients with MPO-ANCA and two of the three patients with PR3-ANCA had clinical vasculitis., Conclusion: PTU is associated with the production of ANCA in patients with hyperthyroidism. PTU-induced ANCA are due to polyclonal activation of B cells. Anti-MPO and anti-PR3 antibodies may associate the occurrence of clinical vasculitis.

The detection rate of antineutrophil cytoplasmic antibodies (ANCA) in Chinese patients with clinically suspected small vessel vasculitis was investigated, and their antigen specificity and demographic features were analyzed. A number of sera (n = 5,604) sent to our referral laboratory for ANCA screening were tested by indirect immunofluorescence (IIF), enzyme-linked immunosorbent assays (ELISAs) for myeloperoxidase (MPO)- and proteinase 3 (PR3)-ANCA. Then the IIF-ANCA-positive sera that were negative for MPO- and PR3-ANCA were further tested by antigen-specific ELISA by using other five highly purified known ANCA antigens as solid-phase ligands. The known antigens included bactericidal/permeability-increasing protein (BPI), human leukocyte elastase (HLE), lactoferrin, cathepsin G, and azurocidins. Of the 5,604 sera, 267 (4.76%) sera were IIF-ANCA positive and 390 (7%) were antinuclear antibody (ANA) positive in the IIF assay. Of the IIF-positive samples, 213 were anti-MPO positive, 32 were anti-PR3 positive, and five cases were positive for both. Of the 48 sera positive for IIF-ANCA but negative for MPO- and PR3-ANCA, 13 sera (27%) recognized other target antigens, 7 sera recognized BPI, 5 recognized HLE, 1 recognize cathepsin G, and 1 recognized azurocidin. None of the sera recognized lactoferrin, and one serum sample recognized both BPI and HLE. The majority of ANCA-positive patients presented in summer or winter. There was no difference in gender (male/female ratio, 1:1.12) in ANCA-positive patients with a mean age of 53.1 years. The male/female ratio was 1.17:1 for patients over 60 years of age; however, it was 1:4 for patients under 20 years of age. We conclude that ANCA-related diseases are not rare in China, and the major antigens are MPO and PR3. When the IIF technique is used to detect ANCA, ANA should be carefully distinguished.

Objective: Anti-neutrophil cytoplasmic antibodies (ANCA) are serological diagnostic markers for certain types small vessel vasculitis including Wegener's granulomatosis and microscopic polyangiitis, which are also termed ANCA associated systemic vasculitis (AASV). The majority of patients with primary AASV reported are adults and predominantly elderly. Data on pediatric patients with primary AASV in China are lacking. This study aimed to analyze the clinical and pathological features of primary AASV in children., Methods: Patients with primary AASV, admitted to the hospital within the past 7 years, were retrospectively studied. The clinical and pathological features were compared between pediatric and adult patients. In pediatric group, there were 20 cases with an average age of (12.1 +/- 4.1) years (aged from 5 to 17 years); in adult group, there were 38 cases with an average age of (55.3 +/- 14.1) years (aged from 20 to 78 years)., Results: The data of this study showed that pediatric patients accounted for 7.87% (20/254) of the whole primary AASV patients. Compared with 38 adult hospitalized patients, pediatric patients were predominantly female (80% vs 50%, P = 0.047). Patients from both groups were microscopic polyangiitis predominantly (95% vs 74%, P > 0.05) and the majority of the sera were P-ANCA/anti-MPO antibody positive in both groups (95% vs 74%, P > 0.05). The prevalence of hypertension in pediatric patients was significantly lower than that in adults (20% vs 61%, P = 0.005). There was no significant difference in clinical manifestations and clinical remission rates between the two groups., Conclusion: Pediatric patients with AASV were not rare in China. The clinical and pathological features of patients with AASV in childhood were similar to adult patients, but there was a female predominance in children.