| Objective:Antineutrophil cytoplasmic antibody(ANCA)associated small vessel vasculitis(AAV)are characterized by the presence of ANCA and the absence of glomerular immune complex deposits.However,many literatures reported that glomerular immune complex deposits were observed in a subset of patients with postive serum ANCA.To better understand the characteristics of antineutrophil cytoplasmic antibody-associated small-vessel vasculitis(AAV)associated with renal glomerular IgA deposition,we investigated the clinical manifestations,renal pathology and prognosis of these patients.Methods:A retrospective analysis was performed at the First Affiliated Hospital of Zhejiang University College of Medicine.The enrolled patients were diagnosed with AAV associated renal injury by renal biopsy from February 2004 to February 2017.We excluded patients with antiglomerular basement membrane antibody nephritis,systemic lupus erythematosus nephritis,Henoch Schonlein purpura nephritis,hepatitis B related Nephritis and other known etiology.According to immunofluorescence examination,the patients were divided into IgA deposition group and pauci-immune complex deposition group;the differences of clinical manifestations,pathological features and prognosis were compared between groups.In addition,we selected the patients of IgA nephropathy and pauci-immune complex deposition AAV according to their age and eGFR.Their serum levels of galactose-deficient IgAl(Gd-IgAl)were tested using enzyme-linked immunosorbent assay(ELISA)and compared among three groups.Results:1.A total of 150 AAV cases were included,25 cases in IgA deposition group and 125 cases in pauci-immune complex deposition group.The level of serum albumin in deposition group was higher than that in pauci-immune complex deposition group(35.0±6.2g/l vs 32.6±5.3g/l,P=0.049),but the titer of MPO-ANCA was lower[24.8(10.43-71.80)U/ml vs 63(21.9-100)U/ml,P=0.044]in IgA depositing group.There were no significant differences between two groups in other laboratory indexes and renal pathological findings.The median follow-up time was 15.2 months in IgA deposition group and 8.9 months in pauci immune complex deposition group,and 28.6%patients in IgA deposition group and 24%patients in pauci immune complex deposition group were in maintaining dialysis;while 8%patients in IgA deposition group and 5.6%patients in pauci immune complex deposition group were died,there were no significant differences between these two groups on patients’ outcomes.2.Cox regression revealed the factors including lower albumin(Odds ratio 0.307,95%confidence interval 0.130 to 0.726,P = 0.007),higher glomerular global sclerosis rate(Odds ratio 3.63,95%confidence interval 1.414 to 9.319,P = 0.007),and more proteinuria(Odds ratio 2.701,95%confidence interval 1.175 to 6.207,P = 0.019)were the independent factors for worse renal outcome.3.The serum Gd-IgAl levels of twenty-five patients from IgA deposition group,pauci-immune complex deposition group and IgA nephropathy group respectively were tested and compared.There was no significant difference between the IgA deposition group and IgA nephropathy group(2315.54±1556.69 ng/ml VS 2420.27±1500.65 ng/ml,P=0.834).However,the Gd-IgA1 levels of IgA deposition group were higher than those from pauci-immune complex deposition group(2315.54±1556.69 ng/ml VS 1731.34±849.11 ng/ml,P=0.198).Conclusion:The clinical features and prognosis of AAV patients with glomerular IgA deposition are similar to those with typical glomerular pauci-immune complex deposition.The serum Gd-IgAl levels of IgA deposition group are parallel with IgA nephropathy group,but higher than those from pauci-immune complex deposition group.Above all,we suggest that those AAV patients with glomerular IgA deposition may be concomitant with IgA nephropathy.At the onset of the diseases,lower blood albumin,more urine protein,higher proportion of sclerotic glomerulus were the independent risk factors for the prognosis of end-stage renal disease. |
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