OBJECTIVETo examine the expression of macrophage migration inhibitory factor (MIF) in renal tissues obtained from children with Henoch-Sch-nlein purpura nephritis (HSPN).

METHODSThe renal tissue samples were obtained from 11 children with different pathological grades of HSPN and 8 children with thin glomerular basement membrane disease (controls). The MIF expression was measured by immunohistochemistry. The correlation between MIF expression and 24 hrs urinary protein excretions was evaluated using a linear correlation analysis.

RESULTSMIF expression was seldom found in renal tissues obtained from controls. However, a significantly increased MIF expression was found and was concordant with the increased severity of renal pathology in renal tissues obtained from children with HSPN. The MIF expression in renal tissues of grade III-IV of renal pathology was significantly higher than that in grade I-II in children with HSPN (p<0.01). In children with HSPN, there was an increased MIF expression in renal tissues with crescent formation and inflammatory cell infiltration. Renal MIF expression was significantly positively correlated with 24 hrs urinary protein excretions in children with HSPN (p<0.01).

CONCLUSIONSMIF may play an important role in renal injury of HSPN. Up-regulation of MIF expression may reflect the degree of renal lesions in HSPN.