title: Autoantibodies and human leucocyte antigen class II in first-degree family members of Mexican-American type 1 diabetic patients.
abstract: As part of a genetic study of type 1 diabetes in Mexican-Americans, 360 first-degree relatives of 108 type 1 diabetic probands were studied. Islet cell antibody (ICA), insulin autoantibody, glutamic acid decarboxylase (GAD(65)), and protein tyrosine phosphatase autoantibodies were measured and human leucocyte antigen (HLA) class II alleles DRB1 and DQB1 genotyping was performed. ICA was positive in 37% of the probands and 5.8% of the relatives. A subgroup of 26 probands (12 ICA+, 14 ICA-) was tested for GAD(65) and was found positive. 4/14 ICA+ first-degree relatives were GAD(65) positive. Four relatives, positive for two antibodies, subsequently developed type 1 diabetes. Life-Table analysis of first-degree relatives with autoantibodies indicated an 80% disease-free survival at 3.5 yr. HLA-DRB1 was found to be associated with the presence of ICA in both probands and relatives, whereas HLA-DPB1 was associated with autoantibody in relatives of type 1 diabetic probands. These results suggest that autoimmunity occurs in type 1 diabetes families of Mexican descent in similar frequencies to that of non-Hispanic, Caucasian families. The presence of autoantibodies appears to be regulated in part by HLA class II genes, even in the absence of overt diabetes.
authors.affiliation: Division of Endocrinology and Diabetes, LAC-USC Medical Center, Keck USC School of Medicine, 1200 North State Street, Los Angeles, CA 90033, USA. azeidler@hsc.usc.edu
authors.forename: A
authors.initials: A
authors.lastname: Zeidler
authors.forename: L J
authors.initials: LJ
authors.lastname: Raffel
authors.forename: G
authors.initials: G
authors.lastname: Costin
authors.forename: S J
authors.initials: SJ
authors.lastname: Shaw
authors.forename: T A
authors.initials: TA
authors.lastname: Buchanan
authors.forename: J
authors.initials: J
authors.lastname: Noble
authors.forename: J I
authors.initials: JI
authors.lastname: Rotter
authors.forename: J
authors.initials: J
authors.lastname: Palmer
authors.forename: J P
authors.initials: JP
authors.lastname: Krischer
authors.forename: C
authors.initials: C
authors.lastname: Wait
authors.forename: N K
authors.initials: NK
authors.lastname: Maclaren
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000208:ethnology / Q000235:genetics / Q000276:immunology*; D005260:Female; D005802:Genes, MHC Class II; D005968:Glutamate Decarboxylase / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000276:immunology; D008297:Male; D017058:Mexican Americans; D008875:Middle Aged
chemical_list: D001323:Autoantibodies; D007328:Insulin; C024211:islet cell antibody; D005968:Glutamate Decarboxylase