OBJECTIVEAnti-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.

METHODSPatients 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).

RESULTSThe 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.

CONCLUSIONPediatric 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.