Does IVIG Get Filtered Out During Dialysis?
No, immunoglobulin G (IVIG) does not get significantly filtered out during dialysis due to its large molecular size (approximately 150 kDa), which exceeds the pore size of standard dialysis membranes.
Molecular Size and Dialysis Membrane Characteristics
- Standard hemodialysis membranes are designed to filter small molecules like urea (60 Da) and creatinine (113 Da), with effective clearance typically limited to molecules under 15-20 kDa 1
- Immunoglobulin G, with a molecular weight of approximately 150 kDa, is far too large to pass through conventional dialysis membrane pores 1
- Even high-flux dialysis membranes, which have larger pore sizes than conventional membranes, do not effectively remove proteins of this size 1
Clinical Evidence in ESRD Patients
- Multiple studies have successfully used IVIG therapy in ESRD patients on dialysis for desensitization prior to kidney transplantation, with standard dosing protocols (2 g/kg monthly) achieving therapeutic effects without requiring dose adjustments for dialysis 2, 3
- In the NIH IG02 trial, IVIG was administered to 101 highly sensitized ESRD patients on dialysis using standard dosing without accounting for dialytic removal, successfully reducing anti-HLA antibody levels and improving transplant rates 3
- The pharmacokinetics of IVIG, including rituximab (a therapeutic immunoglobulin), are not affected by ESRD or dialysis, requiring no dose modification 4
Important Clinical Considerations
Dosing in Dialysis Patients
- IVIG should be dosed the same in dialysis patients as in those with normal renal function, as it is not removed by dialysis 4, 3
- Standard protocols use 2 g/kg administered monthly for desensitization or treatment purposes 2, 3
Monitoring Requirements
- Hemoglobin should be monitored 48-72 hours after IVIG infusion in dialysis patients, particularly those with non-O blood types, due to risk of hemolytic anemia from anti-A/B antibodies in IVIG preparations 2
- Renal function monitoring is less relevant in established ESRD patients already on dialysis, though IVIG can cause acute renal failure in patients with residual kidney function 5, 6
Product Selection Considerations
- Liquid IVIG preparations (Gamunex, Gammagard liquid, Privigen) have higher isohemagglutinin titers and increased hemolysis risk in non-O blood type patients 2
- The incidence of renal impairment with IVIG is approximately 6.7% overall, with irreversible renal failure occurring in 1.7% of cases, though this primarily affects patients with residual renal function 6