title: Development of antirituximab antibodies in children with nephrotic syndrome.
abstract: BACKGROUND
  Rituximab is actively used as a rescue therapy for nephrotic syndrome (NS). The development of antidrug antibodies, including antirituximab antibodies (ARA) and human antichimeric antibodies (HACA), is reported with rituximab treatment in various diseases. Here we report two pediatric patients with NS who developed ARA.
  
  
  METHODS
  Rituximab was given as a rescue therapy for two patients with steroid-dependent NS. Both patients had been treated orally with glucocorticosteroid, methylprednisolone, and calcineurin inhibitors but experienced frequent relapses. With rituximab treatment, the patients remained in remission for several months. After the B-cell count recovered, the patients received a second course of rituximab administration and experienced a hypersensitivity reaction during drug infusion. CD19 cell counts rose despite treatment with rituximab. ARA titers were monitored before and after rituximab treatment, and the development of ARA after the second course of rituximab administration was confirmed.
  
  
  CONCLUSIONS
  We report the development of HACA in two patients with NS who did not achieve B-cell depletion after repeated administration of rituximab. This report suggests that additional studies are needed to determine the incidence of ARA in patients with NS, and its clinical significance.
authors.affiliation: Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea.
authors.forename: Yo Han
authors.initials: YH
authors.lastname: Ahn
authors.forename: Hee Gyung
authors.initials: HG
authors.lastname: Kang
authors.forename: Jiwon M
authors.initials: JM
authors.lastname: Lee
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Choi
authors.forename: Il-Soo
authors.initials: IS
authors.lastname: Ha
authors.forename: Hae Il
authors.initials: HI
authors.lastname: Cheong
mesh_terms: D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000906:Antibodies / Q000276:immunology*; D058846:Antibodies, Monoclonal, Murine-Derived / Q000276:immunology* / Q000627:therapeutic use; D018941:Antigens, CD19; D001402:B-Lymphocytes / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007958:Leukocyte Count; D009404:Nephrotic Syndrome / Q000188:drug therapy / Q000276:immunology*; D011507:Proteinuria / Q000188:drug therapy / Q000209:etiology; D012076:Renal Agents / Q000276:immunology* / Q000627:therapeutic use; D000069283:Rituximab; D013256:Steroids / Q000627:therapeutic use
chemical_list: D000893:Anti-Inflammatory Agents; D000906:Antibodies; D058846:Antibodies, Monoclonal, Murine-Derived; D018941:Antigens, CD19; D012076:Renal Agents; D013256:Steroids; D000069283:Rituximab