title: Contribution of macromolecular IgA1 to IgA abnormality in IgA nephropathy.
abstract: To evaluate the contribution of macromolecular IgA1 to IgA abnormality in childhood IgA nephropathy, serum samples from 29 healthy children and 26 patients with IgA nephropathy in different age-groups (7-9, 10-12, and 13-15 years) were each separated by sucrose density gradient ultracentrifugation and assayed for IgA1 using an enzyme-linked immunosorbent assay. IgA1 in fraction I (sedimentation coefficient >11.4s) was significantly greater in patients 7-15 years of age (median 36.3-57.0 mg/dl) than in the age-matched controls (median 8.8-10.4 mg/dl). IgA1 in fraction II (11.4-9.3s) was significantly greater in patients 10-15 years of age (median 46.7-52.6 mg/dl) than in the controls (median 27.8-35.5 mg/dl), and IgA1 in fraction III (<9.3s) was significantly greater in patients 13-15 years of age (median 156.9 mg/dl) than in the controls (median 120.7 mg/dl). The ratio of IgA1 in fractions I-III was higher in the patients of each age-group (median 0.233-0.314) than in the controls (median 0.067-0.082), while the ratio of IgA1 in fractions II-III was not significantly high in patients 7-12 years old (median 0.268 to 0.318) compared with the controls (median 0.182-0.264). Thus, IgA abnormality in childhood IgA nephropathy would be better represented by an increase in macromolecular IgA1 of >11.4s than by an increase in IgA1 in fractions of 11.4-9.3s or <9.3s.
authors.affiliation: Department of Pediatrics, Hirosaki University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Waga
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Tateyama
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002499:Centrifugation, Density Gradient; D002648:Child; D019281:Dimerization; D004797:Enzyme-Linked Immunosorbent Assay; D005922:Glomerulonephritis, IGA / Q000097:blood / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood* / Q000145:classification*; D007132:Immunoglobulin Isotypes / Q000097:blood / Q000145:classification; D007564:Japan; D012016:Reference Values
chemical_list: D007070:Immunoglobulin A; D007132:Immunoglobulin Isotypes