Low density lipoprotein apheresis ameliorates interferon-γ production in patients with nephrotic syndrome

Rapid amelioration of hypercholesterolemia in nephrotic syndrome (NS) using low density lipoprotein-apheresis (LDL-A) sometimes leads to NS remission, along with improvement of impaired biodefense system; however, the mechanism of how LDL-A affects NS is still unknown. We studied IFN-γ production under IL-12 stimulation for 24 h in whole blood from 30 NS patients, 31 non-NS patients, 35 healthy volunteers and another four persistent NS patients due to refractory focal segmental glomerulonephritis and minimal change type nephrotic syndrome. We compared IFN-γ production in whole blood and peripheral blood mononuclear cells (PBMC) from persistent NS patients before and after each of 14 LDL-A procedures. Finally, we studied the effect that persistent NS patients' serum before and after LDL-A had on IFN-γ production in healthy volunteers' PBMC. Whole blood IFN-γ production was significantly lower in NS patients compared with healthy volunteers or non-NS patients. In persistent NS, after LDL-A, IFN-γ production returned to normal levels. IFN-γ production in PBMC varied greatly among these patients and did not show consistent changes after LDL-A. Healthy volunteers PBMC incubated with persistent NS patients' serum obtained after LDLA showed higher IFN-γ production than before LDL-A. IFN-γ production in peripheral blood is impaired if a patient is in a nephrotic state. LDL-A might restore suppressed PBMC function in persistent NS patients, thereby ameliorating the nephrotic state, possibly through removing interfering serum factors.