title: A prolonged course of Group A streptococcus-associated nephritis: a mild case of dense deposit disease (DDD)?
abstract: We herein report the case of a 12-year-old boy with dense deposit disease (DDD) evoked by streptococcal infection. He had been diagnosed to have asymptomatic hematuria syndrome at the age of 6 during school screening. At 12 years of age, he was found to have macrohematuria and overt proteinuria with hypocomplementemia 2 months after streptococcal pharyngitis. Renal biopsy showed endocapillary proliferative glomerulonephritis with double contours of the glomerular basement membrane. Hypocomplementemia and proteinuria were sustained for over 8 weeks. He was suspected to have dense deposit disease due to intramembranous deposits in the first and the second biopsies. 1 month after treatment with methylprednisolone pulse therapy, proteinuria decreased to a normal level. Microscopic hematuria disappeared 2 years later, but mild hypocomplementemia persisted for more than 7 years. Nephritis-associated plasmin receptor (NAPlr), a nephritic antigen for acute poststreptococcal glomerulonephritis, was found to be positive in the glomeruli for more than 8 weeks. DDD is suggested to be caused by dysgeneration of the alternative pathway due to C3NeF and impaired Factor H activity. A persistent deposition of NAPlr might be one of the factors which lead to complement dysgeneration. A close relationship was suggested to exist between the streptococcal infection and dense deposit disease in this case.
authors.affiliation: 1Department of Pediatrics, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Japan. sawanobori@kmh.kofu.yamanashi.jp
authors.forename: E
authors.initials: E
authors.lastname: Sawanobori
authors.forename: A
authors.initials: A
authors.lastname: Umino
authors.forename: H
authors.initials: H
authors.lastname: Kanai
authors.forename: K
authors.initials: K
authors.lastname: Matsushita
authors.forename: S
authors.initials: S
authors.lastname: Iwasa
authors.forename: H
authors.initials: H
authors.lastname: Kitamura
authors.forename: T
authors.initials: T
authors.lastname: Oda
authors.forename: N
authors.initials: N
authors.lastname: Yoshizawa
authors.forename: K
authors.initials: K
authors.lastname: Sugita
authors.forename: K
authors.initials: K
authors.lastname: Higashida
mesh_terms: D000942:Antigens, Bacterial / Q000648:ultrastructure; D002648:Child; D015432:Glomerulonephritis, Membranoproliferative / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology*; D005938:Glucocorticoids / Q000008:administration & dosage; D006417:Hematuria / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D007668:Kidney / Q000276:immunology / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage; D011507:Proteinuria / Q000188:drug therapy / Q000382:microbiology; D020551:Pulse Therapy, Drug; D011956:Receptors, Cell Surface / Q000648:ultrastructure; D012720:Severity of Illness Index; D013290:Streptococcal Infections / Q000150:complications* / Q000175:diagnosis / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D005938:Glucocorticoids; D011956:Receptors, Cell Surface; C517776:nephritis-associated plasminogen receptor, Streptococcus; D008775:Methylprednisolone