FAVORABLE PROGNOSTIC-SIGNIFICANCE OF RAISED SERUM C3 CONCENTRATION INPATIENTS WITH IDIOPATHIC FOCAL GLOMERULOSCLEROSIS

This study examined the relationship between the clinical and patholog ic variables and renal outcome in patients with idiopathic focal glome rulosclerosis (FGS). The study population included 106 patients with b iopsy proven idiopathic FGS followed for a mean of 31 months. Forty-ni ne patients (46%) maintained stable renal function, 21 patients (20%) had a progressive deterioration of renal function and an additional 36 patients (34%) progressed to end-stage kidney disease. By multivariat e analysis the following baseline variables (i.e. variables measured a t the time of renal biopsy) were associated with the loss of renal fun ction: 1. An elevated serum creatinine; 2. an elevated systemic blood pressure; 3. extensive interstitial fibrosis and tubular atrophy by ki dney biopsy; 4. a low-normal serum C3 level. At baseline serum C3 leve ls were abnormally high in 31 patients (29%). Baseline C3 levels were inversely correlated with baseline serum creatinine levels (p <0.0001) , the severity of histologic changes (p <0.0001), and better preservat ion of renal function during follow-up (p <0.0001). Serum C3 levels di d not correlate with proteinuria or with other clinical variables test ed. The presence of Clq in the mesangium did not correlate with renal outcome. In conclusion, serum C3 levels measured at the time of biopsy correlate with renal outcome in patients with idiopathic FGS. The bas is for this correlation is unknown but it cannot be fully explained by relationships between serum C3 levels and other clinical variables.