title: Antibodies against denatured HLA class II molecules detected in luminex-single antigen assay.
abstract: False-positive anti-HLA reactions may occur in Luminex-single antigen (SA) beads assays, and it is important to recognize them to correctly interpret the test. The purpose of this report is to describe a peculiar pattern of reactivity, characterized by positivity with beads coated with HLA-DRB1*09:01, DRB3*01:01, DRB3*02:02, DRB3*03:01, DPB1*02:01, DPB1*20:01 and DPB1*28:01, that was observed in 141 of 8121 serum samples tested in our laboratory with three different lots of the same kit (LABScreen(®) SA, One Lambda). These 141 serum samples came from 56 different patients on the kidney transplant waiting list, corresponding to 1% of the patients. Of these, 10 males had never been transfused or transplanted. About 66% of the patients had positive reactions against self-antigen HLA-DRB3 alleles. No reactions against native HLA-DRB1*09:01 were observed in flow cytometry crossmatch and in absorption/elution experiments, leading to the conclusion that the reactivity was due to antibodies against epitopes present in denatured forms of HLA-class II antigens. The occurrence of this reactivity pattern was associated with female gender and systemic lupus erythematosus (SLE).
authors.affiliation: Instituto de Imunogenética - Igen, Associação Fundo de Incentivo à Pesquisa, Rua Loefgreen 1235, 04040-031 São Paulo, SP, Brazil. Electronic address: patricia.grenzi@igen.epm.br.
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Grenzi
authors.forename: Renato
authors.initials: R
authors.lastname: de Marco
authors.forename: Rosemeire Z R
authors.initials: RZ
authors.lastname: Silva
authors.forename: Erika F
authors.initials: EF
authors.lastname: Campos
authors.forename: Maria
authors.initials: M
authors.lastname: Gerbase-DeLima
mesh_terms: D000906:Antibodies / Q000097:blood / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D005434:Flow Cytometry; D005787:Gene Frequency; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D007118:Immunoassay / Q000379:methods; D016030:Kidney Transplantation; D008297:Male; D011489:Protein Denaturation; D011933:Reagent Kits, Diagnostic
chemical_list: D000906:Antibodies; D000949:Histocompatibility Antigens Class II; D011933:Reagent Kits, Diagnostic