Urinary IgG and α2-Macroglobulin Are Powerful Predictors of Outcome and Responsiveness to Steroids and Cyclophosphamide in Idiopathic Focal Segmental Glomerulosclerosis with Nephrotic Syndrome

Abstract EN

Objective.

To assess whether high-molecular-weight proteins excretion predicts outcome and therapy-responsiveness in patients with FSGS and nephrotic syndrome.

Research Design and Methods.

Thirty-eight patients measured at biopsy fractional excretion of IgG (FEIgG) and urinary α2-macroglobulin/creatinine ratio (α2m/C).

Low and high risk groups were defined by cutoffs assessed by ROC analysis.

In all patients first-line therapy was with steroids alone or in combination with cyclophosphamide.

Results.

α2m/C and FEIgG were correlated with segmental sclerosis (r=0.546; r=0.522).

Twenty-three patients (61%) entered Remission and 9 (24%) progressed to ESRD.

Comparing low and high risk groups, by univariate analysis remission was predicted by FEIgG (77% versus 25%, P=0.016) and α2m/C (81% versus 17%, P=0.007) and ESRD at best by FEIgG (0% versus 75%, P<0.0001) and α2m/C (4% versus 67%, P<0.0001).

By multivariate analysis FEIgG was the only independent predictor of remission and α2m/C the most powerful predictor of ESRD.

Low and high risk groups of FEIgG and α2m/C in combination had very high predictive value of sustained remission and ESRD in response to therapy.

Conclusions.

FEIgG and α2m/C are powerful predictors of outcome and responsiveness to steroids and cyclophosphamide; their predictive value, if validated in prospective studies, may be useful in clinical practice suggesting first-line alternative treatments in high risk patients.