[Study of the protein C-protein S system in glomerulopathies and nephrotic syndrome]

The protein C-protein S natural anticoagulant system was evaluated in 32 patients with proteinuria, 11 without nephrotic syndrome (NS) and 21 with NS of different grade. Antithrombin III (AT III), factors II, VII, X were also measured in the same groups of patients. In addition to plasma levels of these proteins, urinary loss of protein C was evaluated in concentrated urine specimens from 17 of the 21 patients with NS. The protein C antigen level was found to be normal or high in NS, but the difference between the control group and nephrotic patients was statistically significant only in severe NS. For all proteinuric patients, the plasma concentration of protein C correlated positively with the degree of proteinuria, cholesterol level, triglyceride level, and correlated inversely with serum albumin concentration; 17/17 patients with NS exhibited urinary loss of protein C and the degree of protein C excretion correlated positively with the degree of proteinuria. Plasma protein S antigen was measured in only 11 patients with NS and was found to be significatively increased, with a negative correlation with serum albumin concentration. AT III did not differ between the control group and the proteinuric patients with or without NS. Factors II and X were in the normal range for all patients. Factor VII was increased even in mild NS. Thus, the plasma levels of protein C and protein S antigens were normal or increased in patients with NS and this is probably related to an increased liver synthesis rate of these proteins, which is secondary to proteinuria.(ABSTRACT TRUNCATED AT 250 WORDS)