OBJECTIVE: To study the relationship between α-smooth muscle actin(α-SMA) and clinical symptoms(hypertension and hyperlipoproteinemia ) in children with mesangial proliferative glomerulonephritis(MsPGN). METHODS: Expression of α-SMA was detected using immunohistochemistry and computer image evaluation in 33 children with MsPGN. RESULTS: The expression of α-SMA was higher in MsPGN children with hypertension and/or hyperlipoproteinemia than that in MsPGN children without hypertension and/or hyperlipoproteinemia(P < 0.05). CONCLUSIONS: Expression of α-SMA by mesangial cells appears to be activated by hypertension and hyperlipoproteinemia in children with MsPGN.