title: High-incidence of C9 deficiency throughout Japan: there are no significant differences in incidence among eight areas of Japan.
abstract: From 92,686 sera sent from hospitals throughout Japan to the Special Reference Laboratories for CH50 assay, we were able to classify 80 patients as C9-deficient using a sensitive screening test, as well as hemolytic and immunochemical C9 assays. The incidence of C9 deficiency was determined to be 0.086%, and there were no distinct differences among the eight areas of Japan tested. Serum CH50 levels of these C9-deficient patients varied widely (9.4-63.8 U/ml), and exhibited a higher value (average: 34.1 U/ml) than that of healthy C9-deficient individuals, probably due to elevated C3, C4, and C5 levels. These patients suffered from a variety of autoimmune, renal, and infectious diseases, which, however, are thought to be only incidentally associated with C9 deficiency.
authors.affiliation: Division of Immunoserology, Special Reference Laboratories, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hayama
authors.forename: N
authors.initials: N
authors.lastname: Sugai
authors.forename: S
authors.initials: S
authors.lastname: Tanaka
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: H
authors.initials: H
authors.lastname: Kikuchi
authors.forename: J
authors.initials: J
authors.lastname: Ito
authors.forename: J
authors.initials: J
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Nagata
authors.forename: H
authors.initials: H
authors.lastname: Kondo
authors.forename: O
authors.initials: O
authors.lastname: Harayama
mesh_terms: D003186:Complement C9 / Q000172:deficiency*; D015941:Complement Hemolytic Activity Assay; D005843:Geography; D006801:Humans; D007564:Japan
chemical_list: D003186:Complement C9