title: Recovery of renal function after glucocorticoid therapy for IgG4-related kidney disease with renal dysfunction.
abstract: BACKGROUND
  Although renal dysfunction in IgG4-related kidney disease (IgG4-RKD) shows rapid resolution with glucocorticoid therapy, little is known about the appropriate initial glucocorticoid dose for induction therapy or long-term renal outcome.
  
  
  METHODS
  We retrospectively examined the differences in recovery of renal function according to the dose of glucocorticoid used for induction therapy and the long-term renal outcome in 43 patients with definite IgG4-RKD (mostly IgG4-tubulointerstitial nephritis), in whom the estimated glomerular filtration rate (eGFR) before glucocorticoid therapy was <60 ml/min.
  
  
  RESULTS
  Most patients were treated with glucocorticoid alone and had been maintained on glucocorticoid. The initial dose of prednisolone employed was ≤0.6 mg/kg/day (mean 0.47) in 27 patients (group L), and >0.6 mg/kg/day (mean 0.81) in 16 patients (group H). In both groups, the pretreatment eGFR was significantly improved at 1 month after the start of glucocorticoid therapy and the degree of improvement showed no significant inter-group difference. Relapse of IgG4-RKD occurred in 16.7% of the group L patients and 13.3% of the group H patients (p = 0.78). Among 29 patients who were followed up for over 36 months (mean 74 months) and had been maintained on glucocorticoid, none showed progression to end-stage renal disease and there was no significant difference between eGFR at 1 month after treatment and eGFR at the last review.
  
  
  CONCLUSIONS
  In glucocorticoid monotherapy for IgG4-RKD, a moderate dose is sufficient for induction, and recovery of renal function can be maintained for a long period on low-dose maintenance, although relapse can occur even in patients receiving maintenance therapy.
authors.affiliation: Department of Internal Medicine, Nagaoka Red Cross Hospital, Senshu 2-297-1, Nagaoka, 940-2085, Japan. saekit@nagaoka.jrc.or.jp.
authors.forename: Takako
authors.initials: T
authors.lastname: Saeki
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kanazawa University Hospital, Kanazawa, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawano
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kanazawa University Hospital, Kanazawa, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Mizushima
authors.affiliation: Department of Gastroenterology, Rheumatology and Clinical Immunology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Motohisa
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Wada
authors.affiliation: Nephrology Center and Okinaka Memorial Institute, Toranomon Hospital, Tokyo, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ubara
authors.affiliation: Division of Nephrology and Rheumatology, Department of Internal Medicine, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakashima
authors.affiliation: Department of Internal Medicine, Nagaoka Red Cross Hospital, Senshu 2-297-1, Nagaoka, 940-2085, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Internal Medicine, Nagaoka Red Cross Hospital, Senshu 2-297-1, Nagaoka, 940-2085, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Yamazaki
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Ichiei
authors.initials: I
authors.lastname: Narita
authors.affiliation: General Medical Research Center, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Saito
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D054796:Drug Dosage Calculations; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007564:Japan; D007668:Kidney / Q000187:drug effects* / Q000276:immunology / Q000503:physiopathology; D007674:Kidney Diseases / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology / Q000503:physiopathology; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000276:immunology / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000008:administration & dosage* / Q000009:adverse effects; D020127:Recovery of Function; D012008:Recurrence; D012074:Remission Induction; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D005938:Glucocorticoids; D007074:Immunoglobulin G; D011239:Prednisolone
keywords: Chronic kidney disease; Follow-up; Glucocorticoid; IgG4-related disease; Tubulointerstitial nephritis