Gene expression of
5-lipoxygenase (5-LO) and
leukotriene A(4) (LTA(4))
hydrolase was analyzed in the peripheral blood of 48 children with active primary
nephrotic syndrome (PNS) (group I), 27 children with PNS in remission (group II), and 20 controls. Group I included 34 patients with
steroid-sensitive PNS (SSNS) and 14 patients with
steroid-resistant PNS (SRNS). Total
RNA purified from peripheral blood mononuclear (PBMN) cells was reverse transcribed into
cDNA and amplified with specific primers in the polymerase chain reaction. All group I patients and none of the controls expressed 5-LO and LTA(4 )
hydrolase. Of group II children, 22.2% expressed 5-LO, while 51.9% expressed LTA(4 )
hydrolase. Among group I patients there was a significant positive correlation between the degree of
proteinuria and the expression of 5-LO ( r=0.27, P=0.03) and LTA(4 )
hydrolase ( r=0.44, P=0.001). There was no difference in the degree of expression of both
enzymes between SSNS and SRNS patients. In conclusion,
leukotrienes may play a role in the pathogenesis of PNS in children, but they do not participate in the response of these patients to
steroids.