Background/Aim: To clarify the role of the apolipoprotein E (Apo E) phenoty
pe in IgA nephropathy, we investigated its relationship with histological d
amage and clinical factors. Methods: The subjects were 104 consecutive pati
ents (41 men and 63 women) with IgA nephropathy. The Apo E phenotype was id
entified by plasma isoelectric focusing and immunoblotting, and the frequen
cies of Apo E alleles were calculated. Results: The frequencies of the phen
otypes and the alleles were as follows: 2/2 = 0, 2/3 = 0.086, 3/3 = 0.654,
2/4 = 0.010, 4/3 = 0.211, 4/4 = 0.010, 3/5 = 0.029, epsilon 2 = 0.048, epsi
lon 3 = 0.817, epsilon 4 = 0.120, and others = 0.015. There were no signifi
cant differences between the IgA nephropathy patients and healthy individua
ls in the frequencies of Apo E phenotypes and the alleles. However, the Apo
E2 phenotype was significantly more common among patients with severe hist
ological damage than in those with mild damage. The serum triglyceride leve
ls were significantly elevated, and the Apo E2 phenotype was significantly
more prevalent in patients with severe histological damage as compared with
those with mild damage. Conclusion: The Apo E2 phenotype appears to be ass
ociated with the severity of histological damage in IgA nephropathy.