Is tumor necrosis factor genotype (TNFA2/TNFA2) a genetic prognostic factor of an unfavorable outcome in IgA nephropathy?

The purpose of this study was to examine whether there are the associations between TNF alpha and TNF beta gene polymorphisms and the development and progression of Ig A nephropathy (IgAN). A cross-sectional study on TNF alpha and TNF beta gene polymorphisms by polymerase chain reaction with restriction fragment length polymorphisms was performed on 76 patients with primary IgAN confirmed by renal biopsy and 100 healthy controls. The allele with G -->A substitution was designated as TNFA2 for the TNF alpha gene and TNFB2 for the TNF beta gene. A patient in whom dialysis treatment was started or whose serum creatinine became double or over during the follow-up duration was designated as a "progressor". The TNFA2/TNFA2 genotype was more prevalent in the progressor than in the non-pregressor group (20.0 vs 3.3%, p <0.05). Clinical factors such as serum creatinine, systolic and diastolic blood pressure (p <0.001, respectively) were higher and pathologic factor such as Grade IV or V renal lesions was more prevalent (p <0.01) in the progressor than in the non-progressor group. Therefore, TNFA2/TNFA2 genotype may be a risk factor for the progression of IgAN.