Intravenous immunoglobulin (IVIG) as rescue therapy for BK virus nephropathy

Purpose: BK virus infection is clinically significant in renal transplant recipients, causing BKV-associated nephropathy (BKVN) leading to renal allograft dysfunction and the loss of the renal grafts. The usual management of BKVN involves reduction of immunosuppression, or the addition of leflunomide, quinolones and cidofovir, but the rate of graft loss remains high.   Our aim was to assess the impact of IVIG in treating BKVN in renal transplant recipients.

Methods: Between Sept.2009 to April 2011, a total of 43 renal allograft recipients who were treated with IVIG after diagnosis of BKVN. Upon diagnosis of BKVN by clinical symptoms with BK viremia (viral load >500 copies/mL by PCR), patients were given anti-polyomavirus treatment consisting of reduction of immunosupression and use of leflunomide therapy. Treatment with IVIG was given only to patients who did not respond to those therapies. Patients were treated with IVIG in a 0.5-1.0 gm/kg regimen.  Response to IVIG therapy was monitored by measuring the viral load, serum creatinine level and repeated allograft biopsy if needed clinically. Clearance of viremia (<500 copies/mL) was considered a positive response to IVIG treatment.

Results: There was a significant drop in viral load seen one month after IVIG therapy. Mean peak BK load was 205,314 copies/mL compared to 697 copies/mL after one year follow up. Thirty three patients (84%) had a positive response in clearing viremia. The actuarial patient and graft survival rates after 12-months among the 43 patients receiving IVIG were 100% and 97.4 %, respectively. No serious adverse events from IVIG therapy were observed in these patients. The average total amount of IVIG was 106 56 g per patient and the average cost per patient was $7,682.00.

Conclusion: IVIG appears to be safe and effective in the treatment of BKVN and preventing graft loss in BKVN patients.