Abstract:

Objective  To examine the expression of neutrophil gelatinase associated lipocalin (NGAL) in the kidney tissue, serum and urine in children with Henoch-Schonlein purpura (HSP), and to elucidate its clinical value. Methods  A total of 81 children with HSP were divided into three groups according to urinary albumin excretion rate (UAER): the normal albuminuria group (group A, n=38, UAER<20μg／min), the microalbuminuria group (group B, n=26, 20≤UAER≤200μg／min), and the macroalbuminuria group (group C, n=17, UAER>200μg／min).  Healthy children served as the control group (group D, n=35). The levels of NGAL in the serum and urine were determined by ELISA. Renal biopsy was performed with immunohistochemistry in 22 patients: 5 from group A, 9 from group B, and 8 from group C. Results  There was no significant difference in serum NGAL level in group A and group B compared with group D (P>0.05), but the serum NGAL level was significantly increased in group C(P<0.05). The level of  urinary NGAL was increased in group A, B and C in comparison with group D (P<0.05), and the increase of NGAL was correlated with the degree of albuminuria. The 22 biopsies showed typical morphological changes in Henoch-Schnlein purpura nephritis (HSPN). Furthermore, immunohistochemical staining showed that expression of NGAL in HSP patients were increased especially in group B and C, compared with that in the normal kidney group. Little NGAL expression was found in the normal kidney group. Correlation analysis revealed that the level of urinary NGAL was positively correlated with expression of NGAL in the kidney tissue(r=0.604,P<0.05). Conclusion  NGAL may contribute to renal injury in children with HSP. Examination of the urinary NGAL level may provide a new method for early diagnosis of HSPN.

Key words: Neutrophil gelatinase associated lipocalin; Henoch-schnlein purpura nephritis; Children; Urinary albumin excretion rate