5-Lipoxygenase and leukotriene A4 hydrolase expression in primary nephrotic syndrome.

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.