Use of recombinant human serum albumin in pediatric patients with nephrotic syndrome

Abstract

Sirs, We have read with great interest the article of Dharmaraj et al. [1]. In a clinical setting, some patients with nephrotic syndrome (NS) who are unresponsive to diuretic therapy alone develop severe edema, pleural effusion and ascites. In this context, the administration of human serum albumin in combination with the infusion of loop diuretics is the treatment of choice, although this treatment regimen remains controversial. Since plasma-derived human serum albumin (pHSA) is manufactured from human blood, the supply is limited and the risk of infection by unknown viruses or prions cannot be completely excluded [2]. Recombinant human serum albumin (rHSA) has recently been developed from Pichia pastoris without the use of any animal-derived materials [3], and the clinical use of 25% rHSA for patients suffering from significant albumin loss due to burns, NS and liver cirrhosis, among other conditions, has been approved by the Ministry of Health and Welfare in Japan. Although rHSA has been successfully applied without significant serious adverse effects in the treatment of adult patients with hemorrhagic shock, NS, burns, acute abdominal complaints and liver cirrhosis, poorrisk patients before surgery and post-open heart surgery patients [3–5], little information is currently available on the use of rHSA for the treatment of pediatric patients with NS. Here, we report our preliminary experience of using of rHSA in pediatric patients with NS. Seven patients with NS [four patients with minimal change NS (MCNS), two with focal segmental glomerulosclerosis (FSGS) and one with Henoch–Schonlein purpura nephritis (HSPN)] were initially examined in our study. We started rHSA treatment after receiving both the approval of the ethics committee of our institution and written informed consent from each of the patients and their parents. Specific immunoglobulin (Ig)E antibody titers against Pichia yeast components were measured before the start of rHSA administration. If the serum IgE antibody was positive for Pichia yeast, rHSA administration was prohibited. Of the seven patients initially included in the study, one patient with MCNS who showed weak positivity for serum specific IgE antibody was excluded. The remaining six patients received rHSA treatment in combination with the infusion of loop diuretics for the treatment of refractory edema at Hirosaki University Hospital between September 2008 and January 2009. Among these six patients, one patient with FSGS received three separate rHSA treatments, with the treatment repeated every other month. Thus, a total of eight clinical observations were evaluated. Intravenous rHSA (25% rHSA; Medway, Bipha Co, Chitose, Japan) was administered at a dose of 0.3–0.5 g/kg, one to three times daily in combination with furosemide (1 mg/kg). One treatment course of rHSA was scheduled for at least three consecutive days of administration. Since this study was initially designed mainly to evaluate the safety of rHSA for the treatment of childhood NS, the treatment protocol was individualized according to each patient’s status. Allergic adverse drug reactions to rHSA were carefully monitored during the study period. After 1 month of treatment, a repeat measurement of serum specific IgE antibody against Pichia yeast components was performed, revealing that serum specific IgE antibody for Pichia had remained Pediatr Nephrol (2009) 24:2275–2276 DOI 10.1007/s00467-009-1221-y