Abstract:

ABSTRACT Objective: To investigate the clinic-pathological characteristics and the predictive value of the histopathologic classification in children with systemic small blood vessel vasculitis (SSV)．Methodology: Thirty pediatric patients diagnosed as SSV were collected, and two hundred eighty five adult SSV cases were regarded as controls. The clinic-pathological features and the predictive value of the histopathologic classification were compared between pediatric and adult groups. All patients had renal biopsy and followed up for more than one year. Results: The pediatric cases accounted for 11.8% ( 38/323 ) of SSV patients in the same period. Compared with adult group, the female was predominant in pediatric patients (73.7% vs 51.9%, P<0.05). The main causes of SVV from both groups were microscopic polyangiitis (MPA) (71.1 % vs 72.3 %, P >0.05) and the majority of the sera patterns was P-ANCA/anti-MPO antibody positive (63.2% vs 75.4%, P>0.05). For the first symptom, the prevalence of skin purpura in pediatric patients was significantly higher than that in adults (31.6% vs 6.0%, P<0.01). For the clinical manifestations, the prevalence of of skin purpura was higher and pulmonary lesion was lower in pediatric than that in adults (36.8% vs 13.7%, 26.3% vs 46.0%, P<0.01, P<0.05).There was no significant difference in renal manifestations and laboratory tests such as serum albumin, globulin and baseline creatinine levels except for higher peripheral blood CD8 and lower serum IgG in pediatric than that in adults（all P<0.05）.There were no significant differences for glomerular, interstitial, or tubular lesions between the two groups except for severe PCNA in renal interstitial in pediatric patients (54.36±108.92 vs 14.98±28.95, P<0.05).The patients of focal subtype presented with significantly lower serum creatinine than that sclerotic subtype (P<0.01), crescentic subtype were more likely to respond to treatment and sclerotic subtype patients had worse renal survival in both of pediatric and adult patients. Multiple Cox regression analysis showed that histopathologic classification were predictor for developing ESRD follow-up events in Pediatric patients (HR=2.18 P<0.01).The probability of progressing to ESRD increased with ascending histopathologic classification of focal, crescentic, mixed and sclerotic in pediatric patients (P<0.01). Conclusion: Pediatric patients with SVV were not rare in China. They had a female predominance, higher prevalence of skin purpura, and lower prevalence of pulmonary symptom. The pathological features of the patients in childhood were similar to adult patients, histopathologic classification were predictor for developing ESRD follow-up events in pediatric patients.

Key words: Child, vasculitis, clinical histopathologic, classification prognosis